Staying Healthy on Plant-Based Diets
(Formerly Known As
Staying a Healthy Vegan)
- I was vegan for awhile, but...
- A Candid Discussion About the Vegan Diet
- Position of the American Dietetic Association
- Summary of Health Benefits of a Vegetarian Diet
- U.S. Vegetarians Health: Latest data from the Adventist Health Study
- Current State of Vegan Health
- Diet and Cancer
- Nutrients that Need Attention in Vegan and Vegetarian Diets
- Vitamin B12
- Nutrients that Need Attention in Vegan Diets
- Vitamin D
- Miscellaneous Nutrients
- Non-Protein Amino Acids
- Vitamin A
- Other Nutrients & Multivitamins
- Benefits of Selected Vegan Foods
- Summary of Daily Suggestions for Vegan Adults
- Vegan Multivitamins
For ease in discussion, the following dietary categories are defined:
- Plant-based diet - includes all of the below, from a semi-vegetarian to vegan.
- Semi-vegetarian - eat only small amounts of animal flesh.
- Vegetarian - includes lacto-ovo, lacto-vegetarians, ovo-, and vegans.
- Lacto-ovo-vegetarian - eat no animal flesh, but sometimes eats eggs and dairy products.
- Lacto-vegetarian - eat no animal flesh or eggs, but sometimes eat dairy products.
- Ovo-vegetarian - eat no animal flesh or dairy products, but sometimes eat eggs.
- Vegan - eat no animal flesh, eggs, or dairy products.
Although lacto-ovo vegetarianism has been around for most of human history, the vegan diet appears to be a relatively new experiment - only since the mid-1940s has it been practiced in an organized fashion in the Western world. So far, the experiment appears to be successful: vegans in developed countries have been shown to have the same overall mortality rates as meat-eaters with healthy lifestyles (low smoking and alcohol intake).2 These mortality rates (deaths per year before age 90) are about 50% lower than those of the general population.2 However, there are areas where vegans' health can be improved.
This article has three purposes:
- To help people make the transition to a plant-based diet.
- To give accurate information about the known health benefits of a vegetarian or vegan diet.
- To give people on plant-based diets specific recommendations in order to maximize their health.
I also wrote this article to provide information that other Vegan Outreach members and I wish we had known when we became involved in promoting veganism.
Vegan Outreach promotes a vegan diet in order to lessen the suffering of animals. Since the average American consumes thousands of animals over the course of a lifetime, each person who eats a vegan diet makes a difference by removing their support from the factory farming and slaughtering of these animals. For this reason, I have been involved in vegan advocacy since 1989.
During my years of outreach, I have been told by many people that they tried to be vegetarian or vegan, but hadn't felt healthy. I found this troubling. How can we prevent animal suffering by promoting a vegan diet for our entire society if some people do not respond well to it? Finding an answer to this problem was a major motivation for my becoming a Registered Dietitian. In researching the subject, I discovered that some claims about the vegan diet include distortions or omissions which can lead to people having poor experiences.
For example, some vegan advocates emphasize that humans need only small amounts of B12 and that it can be stored in the body for years. It is true that, at the time they become vegan, some people have enough B12 stored in their liver to prevent serious B12 deficiency for many years. However, people often misinterpret this to mean that you only need to consume a tiny amount of B12 once every few years. Actually, to build up such stores, it takes many years of consuming B12 beyond one's daily needs. Many people do not have large enough stores of B12 to be relied upon even for short periods. This is an easy problem to solve by simply eating B12-fortified foods or taking a supplement.
Nutritional myths have a way of going from one extreme to the other. For example, people once believed that in order to rely on plant protein, you had to combine particular foods at every meal. We now know this is not true. But in countering this myth, claims have gone from "You don't need to combine proteins," to "It's easy to get enough protein on a vegan diet;" to the harmful "It's impossible not to get enough protein!"
On average, vegans get enough protein. In fact, many people trying a vegan diet may choose foods that are high in protein without knowing it. Others may randomly choose foods that are not high in protein. Personally, since I do not feel right when I'm not eating quite a few protein-rich foods each day, I can see how someone else might be ready to quit a vegan diet after a few days of not consuming some protein-rich foods. I fear that many people quickly give up on a vegan diet, thinking it made them feel bad, instead of realizing they might have felt differently had they eaten more protein-rich foods.
This is not to say that every person does better with more protein. Some people report feeling better eating less protein. There are many differences among people and how they respond to various foods.
Eating enough calories might be an issue for an uninformed person who decides to give the vegan diet a try for a few days. Someone on the standard Western diet may only be aware of vegan foods that are low in calories (e.g., salads, vegetables, fruits). Eating only these foods for a day might leave someone unsatisfied and thinking the vegan diet is to blame, when all they needed to do was eat more high-calorie foods.
Again, not everyone needs calorie-dense foods. Some people enjoy the fact that when eating low-calorie foods, they can eat more frequently and a higher volume than ever before without gaining weight; and feel more energetic doing so.
Of course, many advocacy groups are actively trying to educate people about the wide variety of satisfying vegan foods. In promoting the diet, each person could help prepare potential vegans for the real possibility that they won't feel good if they don't choose some calorie-dense foods.
Less noticeable problems can arise due to misinformation. One can find certain studies that support the idea that meat, eggs, and dairy are the cause of osteoporosis, and that calcium intake is not important. Because the arguments can sound impressive, someone might take these claims as fact. Such a person might conclude that a vegan diet must protect against osteoporosis, and that there is no need for vegans to make sure they are getting plenty of calcium and vitamin D. However, selectively choosing such studies leaves out the majority of research published on the subject. Someone who evaluates more of the research will likely conclude that vegans, like non-vegans, should ensure good sources of calcium and vitamin D on a daily basis.
The other nutritional issues of which vegans should be aware are addressed later in this article.
Few long-term, scientific studies have looked at true vegans. A summary of the research on vegetarians and vegans is included in this article. The research has not overwhelmingly supported the idea that a vegan diet is vastly superior to a diet that includes meat or a lacto-ovo vegetarian diet, and some vegans have found this to contradict what they have always heard. How can this be explained?
Popular vegan literature has sometimes presented studies on groups -- such as lacto-ovo vegetarians, semi-vegetarians, cultures that eat little meat, and people who have a high intake of fruits and vegetables -- as indications of the health status of vegans. Although this can provide some useful information about some aspects of the vegan diet, it cannot substitute for studying actual vegans.
Additionally, certain risk factors, such as cholesterol levels, have been used to make projections about the health of vegans, but these do not necessarily tell the whole story. For example, while vegans' cholesterol levels tend to be low, some vegans' low vitamin B12 status can potentially increase their risk for heart disease and stroke. This is easily solved by ensuring a consistent source of B12.
For a concise explanation of the different types of studies and their pros and cons, please see my article, Nutrition Research: What You Should Know.
There are real differences in how people respond to various diets. While many people thrive on a vegan diet, it may not be so easy for others. When someone is committed to reducing animal suffering, there are often solutions to these dilemmas. Affirming everyone's experience is the first step in working with people towards a more humane diet.
I would like to see vegan advocates promote the diet in such a way that we minimize the chances of someone having a bad experience. In so doing, I hope that future, long-term studies on vegans will show us to have even better health than our meat-eating counterparts. Promoting veganism as though there are no nutritional concerns may initially attract more people; but we don't want people merely to go vegan -- we want them to stay vegan.
Position of the American Dietetic Association and Dietitians of Canada: Vegetarian Diets
In their 2003 Position Paper on vegetarian diets, the American Dietetic Association and Dietitians of Canada state, "Well-planned vegan and other types of vegetarian diets are appropriate for all stages of the life cycle, including during pregnancy, lactation, infancy, childhood, and adolescence. Vegetarian diets offer a number of nutritional benefits, including lower levels of saturated fat, cholesterol, and animal protein as well as higher levels of carbohydrates, fiber, magnesium, potassium, folate, and antioxidants such as vitamins C and E and phytochemicals. Vegetarians have been reported to have lower body mass indices than nonvegetarians, as well as lower rates of death from ischemic heart disease; vegetarians also show lower blood cholesterol levels; lower blood pressure; and lower rates of hypertension, type 2 diabetes, and prostate and colon cancer."30
Health Benefits of a Vegetarian Diet, a 1999 paper co-authored by experts on the mortality rates of vegetarians, concludes:
- Compared with non-vegetarians, Western vegetarians have a lower mean BMI (by about 1 kg/m2), a lower mean plasma total cholesterol concentration (by about 0.5 mmol/l [19 mg/dl]), and a lower mortality from IHD [ischemic heart disease] (by about 25%). They may also have a lower risk for some other diseases such as diverticular disease, gallstones and appendicitis. No differences in mortality from common cancers have been established. There is no evidence of adverse effects on mortality. Much more information is needed, particularly on other causes of death, osteoporosis, and long-term health in vegans.12
The Adventist Health Study is the only major study on the general health and mortality of vegetarians in the U.S. Many members of the Seventh-day Adventist Church are vegetarian. Here are some details:
- Data collected from 1976-1988
- 34,192 participants, members of the Seventh-day Adventist church
- 29% were vegetarian
- 7-10% of the vegetarians were vegan.
|Heart disease||38% Lower for Men||No Difference for Women|
|Overall mortality||Lived 3.21 more yrs||Lived 2.52 more yrs|
|BMI - Body Mass Index. A measure
of healthy body weight. Lower than 20 is underweight, while ≥ 25 is
Compared to the non-vegetarians, vegetarians had about:
- 1/2 the high blood pressure and diabetes
- 1/2 the colon cancer
- 2/3 the rheumatoid arthritis and prostate cancer
- Breast, lung, and uterine cancers tended to be lower in vegetarians but could have been due to random chance.
Life expectancies in the Adventist Health Study were published in 2001.27 They showed that white, non-Hispanic Seventh-day Adventists live longer than other white Californians (7.28 years for men, 4.42 years for women). According to the researchers, this group of Seventh-day Adventists were the longest-lived, formally studied population in the world (with an average life span of 78.5 years for men, 82.3 for women).
The following variables were shown to increase life expectancy:
- vegetarian diet
- eating nuts regularly
- physical activity
- lower body weight
- no smoking
The only other variable looked at was hormone replacement therapy for women which possibly contributed to increased life expectancy.27
In 1999, data were published from the 4 largest studies (including the Adventist Health Study mentioned above) analyzing vegan mortality rates.2 The data compared the risk of dying from various diseases between people with different diets but who had similar lifestyles. The standardized mortality ratios (SMR) in 3 of the studies showed less mortality in these groups than in the population at large (no SMR was calculated for the 4th study). Most of this difference was thought to be due to lower smoking rates in the study groups, but some difference may have been due to a generally healthier diet overall than in the population at large.
Compared to 31,766 people who ate meat at least once per week:
Occasional meat eaters (8,135 people who ate meat less than once per week) had a 20% reduced rate of dying of heart disease and a 10% reduced rate of overall mortality.
Those who ate no meat other than fish (2,375 people) had a 34% reduced rate of dying from heart disease and an 18% reduced rate of overall mortality.
Lacto-ovo vegetarians (23,265 people) had a 38% reduced rate of dying from lung cancer, a 34% reduced rate of dying from heart disease, and a 15% reduced rate of mortality.
Vegans (753 people) had a 26% reduced rate of dying from heart disease (however the difference was not statistically significant, meaning that it could have been due to random chance) and their mortality was the same as the regular meat-eaters.
It may come as a surprise that vegetarians have not been shown to have lower rates of mortality from cancer. There has not been enough data on vegans to determine their cancer rates. For a recent summary of the evidence regarding diet and cancer, see Diet, Nutrition and the Prevention of Cancer, by Key TJ, Schatzkin A, Willett WC, Allen NE, Spencer EA, Travis RC. of the Cancer Research UK Epidemiology Unit. An earlier version of this paper is The Effect of Diet on Cancer, by Key TJ, Allen NE, Spencer EA, and Travis RC of the Cancer Research UK Epidemiology Unit.
The acronym "DRI" is used a lot in this article. It stands for Dietary Reference Intake which, to make a long story short, for practical purposes should be thought of as the new term to replace Recommended Dietary Intake (RDA).
There are no reliable, unfortified plant sources of vitamin B12 (See B12 in Tempeh, Seaweeds, Organic Produce, and Other Plant Foods for more information); therefore fortified foods and/or supplements are necessary for the optimal health of vegans and even vegetarians in many cases. Luckily, vitamin B12 is made by bacterial fermentation such that no animal products are necessary to provide it.
There are two types of B12 deficiency: mild and overt.
Overt B12 Deficiency:
B12 protects the nervous system. Without it, permanent damage can result (e.g., blindness, deafness, dementia). Fatigue, and tingling in the hands or feet, can be early signs of deficiency. B12 also keeps the digestive system healthy.
Mild B12 Deficiency:
By lowering homocysteine levels, B12 also reduces the risk of heart disease, stroke, and other diseases. Vegans and near-vegans who do not supplement with vitamin B12 have consistently shown elevated homocysteine levels.
Since 1999, there have been 12 studies comparing the homocysteine levels of vegans and vegetarians who do not supplement their diet with vitamin B12 to those of non-vegetarians. In every study, the vegans or vegetarians had higher homocysteine levels than the meat-eatersand in the range associated with an increased risk of heart disease and stroke.
In contrast, one study compared vegans who supplemented their diets with vitamin B12 (an average of 5.6 mcg/day) with non-vegetarians. Their homocysteine levels were the same, and well within the healthy range. Details can be read in the section Homocysteine, B12, Vegetarians, and Disease of Vitamin B12: Are You Getting It?
If you have been a typical meat eater for most of your life, your body should have stored enough B12 to prevent overt deficiency for a number of years. However, when B12 intake is zero, old B12 stores cannot be relied on to keep homocysteine levels in check.
Vegan infants get B12 through breast milk (their mothers must have a consistent B12 intake) or formula.
The DRI for vitamin B12 is 2.4 micrograms for adults.
- Pangea VeganLife B12 Chewable Supplement 1,000 mcg tablets
- VegLife sublingual 1,000 mcg lozenges. Sold in stores (website has a store locator).
- Freeda Vitamins 500 mcg lozenges
- Nature's Bounty sublingual 2500 mcg
- Solgar sublingual 1,000 mcg nuggets
If you have not had a regular source of B12 for some time, buy a bottle of 1,000 µg (or greater) B12 tablets. The following (and many others) are vegan:
Place 2,000 µg under your tongue until the tablet(s) has dissolved, once a day, for 2 weeks. You can break the remaining tablets in half or quarters for Step #2. It's okay to take more than recommended. Then follow the advice under Step #2.
- 1.5 - 2.5 µg, twice a day, from fortified foods or supplements1
- 10 - 100 µg, once a day, from a supplement1,2
If you have had a regular source of B12, skip Step 1. One of the following daily recommendations should maximize your B12 status:
- In foods, B12 is measured in micrograms (aka "µg" or "mcg"). 1,000 µg = 1 mg.
- The DRI for vitamin B12 is 2.4 micrograms for adults.
- Fortified foods: Amounts listed on a nutrition label are based on 6 µg/day. For example, 25% of the Daily Value = .25 * 6 µg = 1.5 µg.
- Do not rely on any seaweed (e.g., algae, nori, spirulina), brewer's yeast, tempeh, or "living" vitamin supplement that uses plants as a source of B12.
- Do not rely solely on one type of fortified food such as Red Star Nutritional Yeast.
- Vegan infants: The Institute of Medicine recommends that infants of vegan mothers be supplemented with B12 from birth because their stores at birth and their mother's milk supply may be low.3
- Exceptions: People with digestive or malabsorption diseases (such as pernicious anemia), chronic kidney failure, B12 metabolism defects, or cyanide metabolism defects should consult a bona fide health professional.
- Cigarette smokers should consider a non-cyanocobalamin source of B12. Click here for more information.
Click here for an explanation of how these recommendations were formulated.
|Footnotes for Recommendations for Vegans and Near-Vegans|
|1. Lower limit based on minimum recommendations in What Every Vegan
Should Know about Vitamin B12.|
2. In a single dose, B12 absorption drops to 1-1.5% for the amounts above 5 µg.
3. Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline. Washington, DC: National Academy Press; 2000.
See Vitamin B12: Are You Getting It? for more information about B12.
Below is a quick summary about fats simply gives basic recommendations. For a more comprehensive discussion see The Challenge of Defining Optimal Fat Intake by Virginia Messina, MPH, RD, and Making Sense of Fats and Oils by Brenda Davis, RD.
There are two main families: omega-3s and omega-6s.
- Building blocks for hormones that increase inflammation and blood clotting.
- LA (linoleic acid)
- Most prevalent omega-6 in plant foods. Found in corn, sunflower, "vegetable," soy, and safflower oils.
- Since most vegetarians get plenty of omega-6 fats38 they should limit these oils, especially in cooking.
There are 3 important n-3 fatty acids:
- ALA (alpha-Linolenic acid; aka LNA)
- Found mainly in flaxseeds and oil, hemp seeds and oil, camelina oil (aka Gold of Pleasure), walnuts and oil, canola oil, soybeans and oil. Also found in leafy green vegetables and other plant foods, but not in large enough amounts to contribute significantly.
- Reduces blood clotting, improves artery flexibility, and may also reduce heart arrhythmias. LNA shows a strong association with reduced cardiovascular mortality rates, including those from heart attack and stroke.
- EPA (eicosapentaenoic acid)
- Found mainly in fatty fish. Also in irish moss and wakame, but the ratio of iodine to EPA is much too high to make these foods a recommended source.
- Precursor for eicosanoids (hormone-like substances that act on local tissues) which reduce inflammation, blood clotting, and cholesterol.
- DHA (docosahexaenoic acid)
- Found mainly in fatty fish and seaweed.
- Major structural component of the gray matter of the brain, the retina of the eye, and cell membranes.
- Low levels of DHA have been associated with depression.
For some of its benefits, LNA must be converted to EPA which in turn must be converted to eicosanoids or DHA. DHA can also be retroconverted into EPA at a rate of about 10%.36 Although there is no clear evidence that vegans require supplements of DHA or EPA, vegan supplements of DHA are available:
- Deva Vegan Omega-3
In vegetable-based gelcaps; 200 mg of DHA per capsule.
Available from VegetarianVitamin.com
In vegetable-based gelcaps; 300 mg of DHA per capsule.
Available from Pangea and Vegan Essentials.
- Genestra Neurogen DHA
Marketed by Seroyal out of Toronto Ontario. Call 800-263-5861. 100 mg DHA per capsule.
- Neuromins© DHA is available at most health food stores, but it comes in gelatin capsules.
Notes About Flax
- Flaxseeds are the most concentrated source of ALA.
- One teaspoon of flaxseed oil contains 2.5 g of ALA.
- One tablespoon of flaxseeds contains 2.1 g of ALA.
- If flaxseeds are not ground, there is a chance they will not be digested. They can be ground in a blender (works best with a large amount) or coffee grinder, and then stored in the freezer. Ground flaxseeds can be sprinkled on cereal or used in baked goods.
- Cooking flaxseed oil damages the ALA, but it can be put on warm food such as toast. Flaxseed oil should be kept in the refrigerator.
- A straight teaspoon of flaxseed oil does not taste so great. Some people use cinnamon-flavored, tablets, or put it on toast or salad to make it taste better.
Notes About Camelina Oil
- Camelina oil is an oil that supposedly has an n-3:n-6 ratio of 3:1. I only recently found out about it and am not sure of the actual ratio - the USDA does not list camelina oil in their nutrient database.
- Medline lists one study using camelina oil, Effect of alpha-linolenic acid-rich Camelina sativa oil on serum fatty acid composition and serum lipids in hypercholesterolemic subjects (Metabolism. 2002 Oct;51(10):1253-60). In this study, camelina oil fared better than canola (aka rapeseed) and olive oil on LDL cholesterol levels and in increasing EPA and DHA levels.
- Camelina oil can be purchased at http://www.goldofpleasure.com/. However, please note that this site is a commercial site and so anything said should be taken with some skepticism (particularly their anti-flaxseed oil statements which might give the impression that it's difficult to obtain flaxseed oil that isn't rancid; refrigerated flaxseed oil from the store should be just fine). This site says that camelina oil is stable during cooking and is high in vitamin E.
Notes About Hemp
- Hemp seed oil is also a good source but not available everywhere.
Many vegetarians do not get enough omega-3 fats.15 This can result in higher blood clotting which is a risk for heart attack and stroke.
A panel of experts on omega-3 fats has recommended an n-3 intake for nonvegetarians of about 1.3% of calories.37 They recommended an additional 300 mg/d of DHA for pregnant and lactating nonvegetarians. Limiting n-6 intake and increasing intake of ALA to 1.5% of calories will enhance conversion of ALA to EPA and DHA; however, it can sometimes take a few months of following these recommendations to build up DHA. Based on the Recommended Dietary Allowance (RDA) for caloric intake (and subtracting .5% of kcal for usual intake without any supplementation), the following amounts of ALA should be added to the diet:
.9 - 2.0
2.2 - 3.3
An extra .3
An extra .5
An extra .3
An extra .5
|A - Pregnant and lactating
women should consider|
replacing the extra .5 teaspoon of flaxseed oil
with 300 mg (.3 g) of DHA because infants have
more difficulty converting n-3s.
Limit omega-6 Fats
Limiting omega-6 intake is important for maximizing the conversion of omega-3s into EPA and DHA. You should aim for an omega-6 to omega-3 ratio of 4:1 or less. The following sources of n-3s are followed by their approximate ratio of omega-6 to omega-3:
|omega-3 source||approx. n-6:n-3 ratio|
|english walnutsA||4:1 - 5:1|
|AEnglish are the typical walnuts found in most grocery stores.|
Only the top two foods (flaxseeds and canola oil) fall below the recommended ratio of n-6:n-3. This means that other foods will not help decrease the ratio to 4:1, though walnuts will not harm the ratio much while providing a good source of omega-3s.
Flaxseed oil goes a long way in correcting the imbalance in a typical vegetarian diet, but you should only take the recommended amounts.
If you prefer oils on foods such as bread, I recommend raw olive or raw canola oil to minimize your n-6:n-3 ratio as well as for other benefits.
People with diabetes do not efficiently convert ALA to EPA and DHA and should replace .3 grams of ALA with 300 mg of DHA per day.
Parents with prematurely-born infants should contact a health professional about supplementing their diets with essential fatty acids.
Recent, small studies have shown vegans to have the same or slightly worse bone mineral density as non-vegans.5, 6, 7, 8, 9
Factors that can prevent osteoporosis:
- Weight-bearing exercise throughout one's lifetime is one of the most important.
- Adequate calcium, vitamin D, vitamin K, protein, potassium, magnesium, and boron.
- Adequate estrogen levels (for women)
Factors that can contribute to osteoporosis:
- High sodium and caffeine intake
- Excessive amounts of, or too little, protein
Plant foods that provide calcium offer other nutrients that are good for bones: vitamin K in leafy greens; vitamin C, potassium, and magnesium in calcium-fortified orange juice; boron in beans, nuts, leafy green vegetables, and non-citrus fruits.10
The calcium in kale, broccoli, collard greens, and soymilk is absorbed about the same percentage as that in cows' milk.
The calcium in spinach, Swiss chard, and beet greens is not well absorbed, due to their high content of oxalates, which bind calcium.
Many non-dairy milks are now fortified with calcium, vitamin D, and/or vitamin B-12. Many orange juices and other juices are fortified with calcium.
Shake calcium fortified non-dairy milks before pouring as the calcium can settle on the bottom.
Calcium supplements can inhibit iron absorption if eaten at the same time.23
The Daily Value for calcium on food labels is 1,000 mg. Therefore, if a food label says it has 25% of the daily value, it means it has 250 mg of calcium per serving.
Dietary Reference Intake (DRI) for calcium:
|1 - 3||500||2500|
|4 - 8||800||2500|
|9 - 18||1300||2500|
|19 - 50||1000||2500|
|*Do not exceed the upper limit.|
Plant foods high in calcium:
|cow's milk (for comparison)||1 C||300|
|soymilk, fortifiedb||1 C||200-300|
|tofu (if 'calcium-set')||1/2 C||120-300|
|orange juice, fortifiedb||1 C||250|
|blackstrap molasses||1 T||187|
|collard greensa||1/2 C||178|
|sesame seeds||2 T||176|
|veg baked bean||1 C||128|
|navy beans||1 C||128|
|a - Cooked|
b - Read the label for calcium amounts
T - tablespoon
Vitamin D regulates calcium absorption and excretion, especially when calcium intake is low.
There is evidence that some cases of fibromyalgia are misdiagnosed vitamin D deficiency.
Vitamin D can be made by the action of sunlight (UV rays) on skin. Light-skinned, non-elderly adults exposing their hands and face to sunlight during the summer for 10-15 minutes, 2-3 times/week should get enough vitamin D from sunlight. Extra amounts can be stored for during the winter, however, there is some evidence that these stores are not enough for those living in northern climates. See Vitamin D: The Forgotten Nutrient.
Vegans who do not get much sunlight exposure should supplement with vitamin D, especially during the winter or cloudy months.
Elderly people may need up to 4 times,18 and dark-skinned people may need up to 6 times, the amount of sun listed above in order to meet vitamin D needs through sunshine alone. Thus, it is prudent to take a modest vitamin D supplement or use fortified foods.
Vitamin D is not synthesized during the winter in northern climates.10
The only significant, natural sources of vitamin D in foods are fatty fish (e.g. cod liver oil), eggs (if chickens have been fed vitamin D), and possibly some wild mushrooms.18 Most Americans get vitamin D through sunshine, fortified milk, and fortified margarine.
Types of vitamin D:
Vitamin D3 - cholecalciferol; is derived from animal foods or made by the action of ultraviolet light on the skin.
Vitamin D2 - ergocalciferol; a plant chemical that has vitamin D activity in humans, but not as much activity as D3; therefore vegetarians who rely on D2 may need slightly higher intakes.18
One small study found an increase in lumbar spine (lower back) bone density in 4 out of 5 vegans in Finland (a northern country where sunlight does not activate vitamin D during the winter) who took 5 mcg/day of vitamin D2 for 11 months.4
The Daily Value for vitamin D is 10 mcg (400 IU). Therefore, if a food label says it has 25% of the daily value, it means it has 2.5 mcg (100 IU) per serving.
|Dietary Reference Intake (DRI) for vitamin D|
|Age (yrs)||DRI mcg(b) (IU)||Upper LimitA|
|< 1||5 (200)||25 (1000)|
|1-50 yrs old (incl. pregnancy)||5 (200)||50 (2000)|
|51-70 yrs||10 (400)||50 (2000)|
|Over 70||15 (600)||50 (2000)|
|A - Do not exceed the upper
B - mcg = microgram = µg
Sources of Vitamin D:
Iodine is needed for healthy thyroid function which regulates metabolism. Both too much, and too little, iodine can result in abnormal thyroid metabolism.
Studies have shown that vegans in Europe (where salt is either not iodized or not iodized at high enough levels) who do not supplement (as well as those who oversupplement) have indications of abnormal thyroid function.19,20
Iodine is found in produce grown in some parts of the country, but in very small amounts. Iodine deficiency is not as much of a problem for U.S. vegans as it is for European vegans,19,20 whose food supply contains less iodine. North American vegans should take a modest iodine supplement on a regular basis to ensure they are meeting requirements because it's very hard to predict how much is in any given person's food supply. 75-100 mcg every few days should be ample.
Avoid intakes in excess of the Upper Limit.
|Dietary Reference Intake (DRI) for Iodine|
|1 - 3||90||200|
|4 - 8||90||300|
|9 - 13||120||600|
|A - Do not exceed the upper
B - mcg = microgram = µg
Vegan iodine supplements can be found in most grocery or natural food stores. Most vegan multivitamins contain iodine.
More details on iodine from the UK Vegan Society. An excerpt:
- ...Iodine deficiency during pregnancy and early infancy can result in
cretinism (irreversible mental retardation and severe motor impairments)....
Hypothyroidism can manifest as low energy levels, dry or scaly or yellowish
skin, tingling and numbness in extremities, weight gain, forgetfulness,
personality changes, depression, anaemia, and prolonged and heavy periods in
women.... Hypothyroidism can also cause carpal tunnel syndrome and Raynaud's
phenomenon [episodes of
blood flow loss to the fingers, toes, ears, and nose]. Hypothyroidism can
lead to significant increases in cholesterol levels and homocysteine levels
and is implicated in about 10% of cases of high cholesterol levels. Correcting
hypothyroidism can lead to a 30% drop in cholesterol and homocysteine levels.
And even more on iodine.
It was once believed that vegetarians (and vegans) needed to combine protein sources at each meal to get "complete protein." Now we know that protein combining at each meal is not necessary.
In their Position Paper on Vegetarian Diets, The American Dietetic Association states:
- "Plant protein can meet requirements when a variety of plant foods is
consumed and energy needs are met. Research indicates that an assortment of
plant foods eaten over the course of a day can provide all essential amino
acids and ensure adequate nitrogen retention and use in healthy adults, thus
complementary proteins do not need to be consumed at the same meal."
|Protein Recommendations for Young Vegans|
|1 - 2||18-19||18-19|
|2 - 3||18-21||18-21|
|4 - 6||26-28||26-28|
|7 - 10||31-34||31-34|
|11 - 14||51-55||50-54|
|15 - 18||50-55||66-73|
The plant foods highest in protein are legumes (beans, peanuts, soyfoods such as tofu) and nuts, but grains and vegetables also contribute significant amounts.
|Protein Content of Common Vegan Foods|
|Naturade soy protein powder||1/3 Cup||23 g|
|Naturade soy-free protein powder||1/3 Cup||22 g|
|Tofu||1/2 Cup||10 - 20|
|Veggie dog/burger||1||6 - 18|
|Texturized soy protein||1/2 Cup||11|
|Soymilk||1 Cup||5 - 10|
|Peanut butter||2 Tablespoons||8|
|Refried beans*||1/2 Cup||6.9|
|Sunflower seeds||1/4 Cup||6.2|
|Oatmeal*||1 Cup, instant||5.9|
|Brown rice*||1 Cup||5|
|Broccoli*||1 Cup chopped||4.6|
|Potato, baked||1 medium||4.5|
|Walnuts||1/2 oz (7 halves)||4.3|
|White rice*||1 Cup||4.1|
|Almonds||1/2 oz (12 kernels)||3|
|Kale*||1 Cup chopped||2.5|
|Taco shell||1 medium||1|
Click here to check the USDA National Nutrient Database for the content of protein or other nutrients in foods.
Vegans might not meet their protein needs, resulting in a loss of muscle mass and/or reduced immunity, if:
- Food intake does not meet energy needs such as in cases of anorexia nervosa, depression, poverty, lack of appetite due to illness,3 or dieting.
- Higher-protein plant foods are not included in sufficient amounts. This
can happen when:
- Most food eaten is junk food such as French fries, soda, etc.
- Protein is believed to be unimportant and/or higher protein foods are avoided (such as in some fruitarian or raw food diets).
- Legumes are avoided.3 (Other high-protein foods should be used.)
Vegan athletes interested in how much protein they need should see:
Vegetarian Diet for Exercise and Athletic Training and Performing: An Update by D. Enette Larson, MS, RD, LD.11
For more information on the amino acid DRIs and content of plant foods, see Where Do You Get Your Protein?
Taurine and carnitine are non-essential amino acids found primarily in animal products. If you are eating enough protein, your body should make what you need. If you go an extended period of time without eating enough protein, or if you have a metabolic problem, you might benefit from a period of supplementation. In such cases, it is prudent to contact a health professional. There is no reason for most vegetarians or vegans to be concerned.
A carnitine metabolic problem has been linked to migraines. If you are a vegan who started getting migraines after becoming vegan, you might consider talking to your health professional about carnitine supplementation.
Creatine is a combination of the amino acids glycine, arginine, and parts of methionine. It is used in skeletal muscle for quick energy. The body can make its own creatine. It is in animal flesh, but not plant foods.
Because vegetarians do not eat any creatine (the average intake for a meat-eater is 2 g/day11), it is thought that vegetarian athletes might benefit from supplementation. Manufacturers claim that creatine supplements are synthesized from non-animal products.11 Before taking creatine, vegetarian athletes should read up on the subject such as in the article by Larson11 and the section on creatine in Becoming Vegan3.
Iron-deficiency anemia is probably one of the most inaccurately self-diagnosed illnesses. Only a medical doctor can diagnose it properly and people who think they may be suffering from it should see a doctor.
Iron-deficiency symptoms include pale skin, brittle fingernails, fatigue, weakness, difficulty breathing upon exertion, inadequate temperature regulation, loss of appetite, and apathy.
Iron in vegetarian diets is a somewhat controversial topic for a number of reasons.
Iron is prevalent in many plant foods.
|Iron Content of Common Foods|
|fortified cereals||1/2 C||varies|
|blackstrap molasses||1 T||3.3|
|pumpkin seeds||2 T||2.5|
|pinto beansA||1/2 C||2.2|
|apricots, dried||1/4 C||1.5|
|A - Cooked; T - tablespoon|
But, while vegans normally have as high, or higher, iron intakes as non-vegetarians, plant iron is normally not absorbed as well as iron from meat.
Because of this lower absorption, vegetarians' ferritin (the storage form of iron) levels are often lower than non-vegetarians. Even with the lower amounts of stored iron, cross-sectional studies to date have not shown higher rates of iron-deficiency anemia among vegetarians. But despite the fact that no differences in anemia have been found, it does not rule out the possibility that there are people (especially menstruating women) who stop being vegetarian after feeling the effects of lower iron absorption.
I have met many ex-vegetarian women (and a few men) who claimed to become anemic after becoming vegetarian. In most cases, they did not have a doctor diagnose them. Rather, they just assumed they were anemic because they were tired. This could be due to numerous things, such as not eating enough calories, protein, or eating too many high-sugar, refined foods. But, I have heard it enough that I do think there is a possibility that some women have a hard time with the lower iron absorptoin of plant foods, especially when first becoming vegetarian.
I say that iron absorption may be more of a problem when people first become vegetarian because long-term studies of vegetarian women have not shown high drop out rates. Physiologically, it makes some sense that the problem would tend to show up right away or not at all, for the following reason.
The body secretes a transport protein, transferrin, into the digestive tract when iron stores are low. This protein helps shuttle iron from the food you eat into the bloodstream. If someone has been a meat-eater all her life, her body has not had a need to manufacture as much transferrin as she might need as a vegetarian. This might cause a quick drop in iron absorption once she becomes a vegetarian. Someone's body may or may not become more efficient at producing transferrin over time, but if she becomes anemic right away she will likely quit the diet and not give her body the chance.
Of course, there are ways around this. Vitamin C significantly aids in iron absorption (the iron and vitamin C must be eaten at the same meal). In one study, vegetarian children with iron deficiency anemia in India, were given 100 mg of vitamin C at both lunch and dinner for 60 days. They saw a drastic improvement in their anemia with most making a full recovery.39 And, of course, there are iron supplements.
Calcium supplements, coffee, and tea inhibit iron absorption if eaten at the same time as iron, so avoid them at meals in which you are trying to increase iron absorption.23
For more information, see What should I do if my doctor tells me to eat meat because I have iron deficiency anemia?
On a personal note, a few years ago I was feeling more tired than normal during workouts. I thought maybe I was suffering from anemia, so I had it checked. I was fine. I decided to eat more food, put on a few pounds, and my level of energy returned and I have felt energetic ever since.
Anemia is a possible downside to lower iron absorptions, but there are a few potential upsides:
- 1. Low iron stores are associated with higher glucose tolerance and
therefore could prevent diabetes.
- 2. High iron stores have been linked to heart disease. Based on an early
study, this was believed to be a strong link for a number of years. Now that
more evidence has come in, the link appears to be only in cases of very high
iron storage levels, such as greater than 200 mcg/l (vegans' ferritin levels
are rarely above 100 mcg/l). For now, the Food and Nutrition Board of the
Institute of Medicine says, "This body of evidence does not provide convincing
support for a causal relationship between the level of dietary iron intake and
the risk for CHD [coronary heart disease]."32
- 3. High iron stores have been linked to cancer. The association with
cancer appears stronger than for heart disease.
Hemochromatosis is a disease of increased iron absorption. Its most serious, homozygous form occurs in about 1 in 100 blacks and 1 in 200 nonblacks. Its less serious, heterozygous form occurs in 30% of blacks and 12% of nonblacks.33 Most affected people do not know they have the disease.33 People with hemochromatosis are at risk for cirrhosis,33 liver cancer,32 and other diseases. Alcoholic cirrhosis, other liver diseases, iron-loading abnormalities, and other rare diseases can also cause iron overload.32
The Upper Limit for iron is set to prevent gastrointestinal distress and not to prevent possible chronic diseases from iron overload.32
Amounts listed on a nutrition label are based on 18 mg/day.
For example, 25% of the Daily Value = .25 * 18 mg = 4.5 mg.
The new U.S. DRIs for iron distinguished between vegetarians and nonvegetarians. The DRI for vegetarians was determined by increasing the regular DRI by 1.8 times.21 However, this is very controversial because the recommendations were not based on studies of vegetarians. Most vegetarian dietitians do not think it is necessary to get this much iron. For that reason, the DRI's for non-vegetarians are listed here.
|Dietary Reference Intake (DRI) for Iron|
|.5 - 1||11||40|
|1 - 3||7||40|
|4 - 8||10||40|
|9 - 13||8||40|
|breastfeeding females, 14-18||10||45|
|breastfeeding women 19-50||9||45|
|A - Do not exceed the upper
Those who engage in regular, intense exercise may need an additional 30%.21
Recommendations for Iron
You do not need to worry about iron if you are otherwise healthy and eat a varied vegetarian or vegan diet. If you suspect an iron deficiency, see a doctor. If your doctor thinks your iron stores are too low, eating meat (which is unnecessary) or taking an iron supplement may be suggested. Taking a 100 mg vitamin C tablet with two meals a day for 60 days, and refraining from tea and coffee during meals, should improve the anemia. If not, consult a doctor about iron supplementation.
Zinc is not found in large amounts in plant foods, but vegetarians tend to have adequate zinc status. Zinc is found in legumes, nuts, corn, peas, cashews, peanuts, peanut butter, pumpkin seeds, and sunflower seeds; cereals are often fortified with zinc.
Symptoms of zinc deficiency include poor growth and delayed sexual maturation in children, poor wound healing, hair loss, impaired immune function, and dermatitis (especially around body orifices).23
Protein increases zinc absorption. Because of this, foods high in protein and zinc, such as legumes and nuts, are good choices.26 The leavening of bread (most bread is leavened) and fermenting of soyfoods (tempeh and miso) also enhances zinc absorption.26
Selenium intake is more related to the selenium content of the soil than to
dietary pattern. U.S. and Canadian soil appears to be adequate in selenium.
Studies of vegetarians and vegans in the U.S. have shown them to have adequate
intakes. Selenium is found in many foods, but in higher amounts in Brazil nuts,
whole grains (whole-wheat bread, oatmeal, barley), white rice, and beans.22
Pre-formed vitamin A exists only in animal products. However, there are about 50 carotenoids that the body can convert into vitamin A; the most common is beta-carotene. The vitamin A content of foods is now stated as retinol activity equivalents (RAE). The DRI of 900 RAE for men and 700 RAE for women, can be met with:
|Baked Sweet Potato||1 Medium||1244|
|RAE - Retinal activity
Other sources include kale, mango, spinach, butternut squash, and various greens.
Other Nutrients & Multivitamins
Some people may have specific problems absorbing or utilizing certain nutrients (regardless of their diet). Some nutrients are normally provided adequately by a varied vegan diet, but can be low in some vegans' diets. Riboflavin (vitamin B2) and pyridoxine (vitamin B6) are two examples. While most vegans have no problem with vitamin B6, numerous members of one vegan family showed symptoms of vitamin B6 deficiency.24
Symptoms of vitamin B2 deficiency are sores outside of the lips and in the corners of the mouth, swollen tongue and mouth cavity, and dermatitis.23 Vitamin B2 is found in a wide variety of plant foods in small amounts, including avocados, mushrooms, almonds, leafy green vegetables, and soybeans.26
Cereals fortified with iron, zinc, and B vitamins can add some ensurance of getting adequate amounts.
Some researchers suggest taking a modest multivitamin supplement regardless of your diet. I recommend one that is about 25-100% of the DRIs. B vitamins can be taken in higher amounts. Tablets can be broken in half.here (opens in new window) to read the article, Vegan Pregnancy, by Reed Mangels, PhD, RD. from the Jan/Feb 1997 issue of The Vegetarian Journal.
The American Dietetic Association and the American Academy of Pediatrics agree that well-planned vegan diets can satisfy the nutrient needs and normal growth of infants.25
Breast-feeding is the best option when possible. Vegan parents should not try to make their own infant formulas as this often leads to poor child development. Although more research is desirable, it appears that soy infant formulas are generally safe. See below for information regarding soy formulas.
Breast milk is low in vitamin D and varies according to the mother's intake/sun exposure. According to some experts, dark-skinned, breast-fed babies should be given vitamin D supplements.18
For more information see:
- Feeding Vegan Kids by Reed Mangels, PhD, RD
- May 2002 VRG-News by Reed Mangels, PhD, RD
- The book Becoming Vegan by Brenda Davis, RD and Vesanto Melina, MS, RD
If you need to feed your baby formula, soy formulas are available. Unfortunately, they all contain vitamin D3 which usually comes from sheep's wool or fish. As of 2001, the following brands were vegan except for the vitamin D3:
Click here for thoughts on the subject of trying to be 100% vegan.
Are infant soy formulas safe?
Infant soy formulas have been around for many years and used without apparent problems. However, there has recently been a concern that the isoflavones in soy could be harmful for infants.
Click here for an abstract of the only long-term study comparing infants receiving cow's milk formula to infants receiving soy formula.
Click here for an abstract of a more recent review of the subject.
Click here for an article about a recent, ongoing study of soy infant formulas conducted by the Agricultural Research Service of the USDA. A summary of the article is that there have been no observed negative effects of soy formulas in humans but some animal research has raised concerns that soy formulas may cause infants to metabolize drugs abnormally fast. While this has not yet been directly studied in human infants, it seems that researchers looking at other aspects of soy formulas' effects on infants would have observed manifestations of abnormally fast drug metabolism if it were a common or serious problem.
For more information, see:
- Feeding Vegan Kids by Reed Mangels, PhD, RD
- The book Raising Vegetarian Children by Joanne Stepaniak, MS ED and Vesanto Melina, MS, RD.
Fiber and Children
The American Academy of Pediatrics recommends that children eat no more than .23 g of fiber per pound of body weight per day. Vegan children can easily exceed this limit. They might come closer to recommendations by eating half of their servings of grains as refined grains (e.g., white pasta, white rice, white bread).26
Vegan children who do not eat much because they get full easily may benefit from eating some low-fiber foods such as refined grains, peeled fruits and vegetables, and added oils.26 Nuts and nut butters can also increase their calorie and protein intake. For younger children, be sure to chop or grind nuts well enough to prevent choking.
Beans and Nuts
In addition to being excellent sources of protein, beans and nuts have many other benefits such as vitamins, minerals, fiber, and other chemicals that may prevent cancer and heart disease.28,29 Nuts also contain monounsaturated fats which are healthy for the heart. In one study, eating nuts (including peanuts34) 5 or more times per week reduced heart disease by about 50%!1
Fruit and Vegetables
High fruit and vegetable consumption has been associated with a reduced risk for cardiovascular disease, several common cancers, and other chronic diseases (such as macular degeneration and cataracts).
Whole-grain consumption has been associated with a reduced risk for heart disease, diabetes, hypertension, and stomach and colon cancer. Whole grains include brown rice, whole-wheat bread, barley, oatmeal, corn, quinoa, and millet.
|Recommended Daily IntakesA|
|Vitamin B12||3-100 mcg (µg)|
|Omega-3 fats||2.2 - 3.3 g; about 1 tsp of flaxseed oil or 1 Tbsp of ground flaxseeds|
|Calcium||1000 - 1200 mg; (i.e., 3 servings of high-calcium foods or supplements)|
|Vitamin D||5-15 mcg (200-600 IU)|
|Iodine||75 - 150 mcg every few days|
|General Health||Plenty of green and yellow vegetables, other vegetables, fruits, nuts, legumes, and whole grains|
|A - See individual sections for
needs of other age groups.|
Companies often change the amount of vitamins and minerals in their multivitamin supplements. The information below was as of the last time I checked.
Click here for thoughts on the subject of trying to be 100% vegan.
|Country Life in health food
|125||none||2.5 (100)||60 T||$12|
Available from: Bodybuilding.com and VegetarianVitamin.com
|50||150||10 (400)||90 T||$13|
|Deva Nutrition iron-free vegan multivitamin||100||150||10 (400)||90 T||$13|
Freedavite Tiny Tablet Multi-Vitamin & MineralB
|6||75||10 (400)||250 T||$13|
|100||50||3.3 (133)||90 T||$13|
|75||38||2.5 (100)||120 C||$18|
VegLife in health food stores
|A - microgram = mcg = µg|
B - Company says their vitamin A (palmitate) and D are from non-animal sources.
C - Numbers are calculated per tablet (T) or capsule (C).
Other vegan multivitamins:
|Futurebiotics Vegetarian Super Multi||futurebiotics.com|
|KAL Vegetarian Multiple||1-800-733-4525|
|Nature's Life vegetarian Mega-Vita-Min iron free||natlife.com|
|Freeda Ultra, iron-free
Freeda Quintabs-m, iron-free
Ultra Freeda, A-Free (w/Iron)