Demystifying Vegan Nutrition: A Starter Guide

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What is a vegan diet?

A vegan diet is one that consists of only plant-derived foods, as vegans do not use or consume any animals or animal products, including flesh, eggs, and milk. Like non-vegans, vegans eat soups, stews, stir-fries, salads, and casseroles. They may consume a wide variety of ethnic foods, as well as vegan versions of traditional favorites such as pizza, tacos, burritos, lasagna, burgers, barbeques, loaves, chili, pancakes, waffles, sandwiches, and desserts.

What is a healthful vegan diet?

A balanced vegan diet is made up of these four food groups: 1) legumes, nuts, and seeds; 2) grains; 3) vegetables; and 4) fruits. Because individual nutrient needs and energy requirements vary due to age, activity level, and one’s state of health, this guide should only be considered a broad blueprint for a balanced vegan diet. Consult a dietitian familiar with vegan nutrition for a personalized set of recommendations.

LEGUMES, NUTS, AND SEEDS (4+ servings per day)

The legume-nut-seed group includes beans, split peas, lentils, nuts, seeds, and soy products. These nutrient-dense foods are packed with protein, fiber, minerals, B vitamins, protective antioxidants, and essential fatty acids(1). Sample serving sizes from this group include: ½ cup cooked beans, 4 ounces of tofu or tempeh, 1 cup soy milk, 1 ounce of nuts or seeds, or 2 tablespoons of nut or seed butter.

GRAINS (4-6+ servings per day)

Whole grains provide B vitamins, fiber, minerals, protein, and antioxidants. They are preferable to refined grains because the refining process removes the healthiest nutrients. Also, intact whole grains--such as brown rice, oats, wheat berries, millet, and quinoa--are nutritionally superior to whole grain flours and puffed or flaked whole grains(2). A serving is one slice of bread, ½ cup cooked grain, or 1 ounce of ready-to-eat cereal. This group is fairly flexible with regard to servings per day. Vary your intake based on your individual energy needs.

VEGETABLES (4+ servings per day)

Eating a wide variety of colorful vegetables every day will ensure that you’re getting an assortment of protective nutrients in your diet(3). A vegetable serving is ½ cup cooked, 1 cup raw, or ½ cup vegetable juice. For most vegetables, particularly calcium-rich leafy greens, it’s nearly impossible to eat “too much.”

FRUITS (2+ servings per day)

Most fruits, especially citrus fruits and berries, are a great source of vitamin C; all fruits provide antioxidants and fiber. Choose whole fruits over fruit juices to get the most benefit, particularly from dietary fiber. A serving size is one medium piece, 1 cup sliced fruit, ¼ cup dried, or ½ cup of juice.

A few words about fats

Concentrated fats, such as oils and oil-based spreads, do not fall under a food group. They are not required for optimal health, as essential fats are found naturally in whole foods like avocados, olives, nuts, and seeds, and for that reason there is no serving recommendation. However, a small amount of these fats--a serving is 1 teaspoon--may be included in a healthful vegan diet. Choose oils and spreads that are minimally processed and limit your intake.

How healthy is a vegan diet?

According to the American Dietetic Association’s 2009 Position Paper on Vegetarian Diets, vegan diets “are healthful, nutritionally adequate, and may provide health benefits in the prevention and treatment of certain diseases.” A healthy vegan diet helps reduce your risk of heart disease, cancer, obesity, and diabetes(5).

The scoop on some important nutrients

Like non-vegans, vegans need to be mindful of consuming all the nutrients they need in order to be healthy. Three nutrients that everyone needs to pay attention to are vitamin B12, vitamin D, and omega-3 fatty acids.

Vitamin B12 is necessary for proper red blood cell formation, neurological function, and DNA synthesis(6). It is manufactured by certain types of bacteria found in nature. Because plants vary widely in their levels of this bacteria (and most of us favor our food scrubbed squeaky clean), we cannot rely on plant foods to meet our B12 needs. We can ensure our dietary needs are met by consuming supplements and/or fortified foods. Our suggestion is to supplement with a vegan source of 2000 micrograms once a week or 10-100 micrograms a day (be advised that some B-12 vitamins labelled as vegetarian are in a stomach base). Or, if you prefer not to use supplements, consume at least three servings of vitamin B12-fortified food per day (each supplying at least 20% of the Daily Value on the label), such as nondairy milks, breakfast cereals, meal replacement bars, beverage mixes, and Red Star Vegetarian Support Formula Nutritional Yeast (read labels to ensure B12 content).

Vitamin D, the “sunshine vitamin”, is also a hormone; our skin manufactures it from the ultraviolet rays of the sun. It plays an important role in bone health and supports normal neuromuscular and immune function(7). Good vitamin D status is linked to a lowered risk of osteoporosis, certain cancers, and other chronic diseases(8).

Vitamin D blood levels are an international public health concern. Getting enough of it is not as easy as we may think. The body’s ability to produce vitamin D from sun exposure varies based on skin pigmentation, sunscreen, clothing, time of year(9)(10), latitude, air pollution, and other factors, and the vitamin is found naturally in only a handful of foods. This is why all people--not just vegans--need to be mindful about vitamin D. The latest research suggest that getting even 100% of the current Recommended Dietary Allowance (RDA) for vitamin D may be insufficient for many people. To ensure adequate vitamin D intake, take 1000-4000 International Units (IU) per day, depending upon your age and other individual needs(11).

Regardless of whether you eat a vegan diet, you may want to test your vitamin D status at your next medical checkup. Schedule a 25(OH)D (25-hydroxyvitamin D) blood test, and your healthcare provider can offer supplement guidelines based on the results.

Supplemental vitamin D comes in two forms: vegan D2 (ergocalciferol), usually synthetic or manufactured from yeast, and non-vegan D3 (cholecalciferol), manufactured from lanolin (from sheep’s wool)(12).

Omega-3 fatty acids. A proper balance of essential fats is important for optimal brain function, heart health, and infant/child development(13). Alpha-linolenic acid (ALA) is an omega-3 fatty acid that partly converts to DHA and EPA in the body. It is present in several plant foods, including flax products, hemp products, canola oil, walnuts, and leafy green vegetables. Aim to consume 2 to 4 grams of ALA per day(14):

food/serving size ALA (grams)
Flaxseed oil, 1 Tbsp. 8.0
Flaxseed, whole, 2 Tbsp. 5.2
Flaxseed, ground, 2 Tbsp. 3.8
Hempseed oil, 1 Tbsp. 2.7
Walnuts, 1 oz (1/4 cup) 2.6
Canola oil, 1 Tbsp. 1.6
Tofu, firm, ½ cup 0.7
Greens (mixed), 2 cups 0.2

If you aren’t sure whether your intake is adequate, you may wish to take up to 300 milligrams of algae-based DHA or DHA-EPA blend per day.

What about calcium?

Calcium is naturally widespread in the plant kingdom, and so our calcium needs can be met with whole plant foods (and, optionally, calcium-fortified foods). Adults need about 1000 milligrams per day, though the amount depends on one’s stage in the lifecycle(15). We recommend choosing several calcium-rich foods in each food group each day. Some of the richest plant sources of calcium are: leafy green vegetables, figs, almonds and other nuts, sesame and other seeds, beans, calcium-set tofu, fortified nondairy yogurt, fortified soy products, fortified breakfast cereals, and fortified fruit juice.

Food/serving size(16) Calcium (mg)
Calcium-set tofu, ½ cup 140-420
Fortified soy milk, 1 cup 200-370
Collard greens, 1 cup cooked 270-360
Fortified orange juice 300-350
Soy yogurt, 1 cup 150-350
Amaranth, 1 cup (cooked) 275
Broccoli rabe/Rapini, ½ bunch (cooked) 260
Sesame seeds (unhulled), 2 Tbsp. 175
Blackstrap molasses, 1 Tbsp. 80-170
Navy beans, 1 cup (cooked) 160
Bok choy, 1 cup (cooked) 160
Figs, 5 large (raw) 110
Almonds, 1 oz 70

Note: Calcium content varies depending on variety, brand, and origin.

What about iron?

Iron is a mineral used by the body to carry oxygen from our lungs to the rest of the body, among other functions. When we don't get enough iron, it can lead to fatigue, cognitive impairment, and other health problems. Iron deficiency is the most common nutrient deficiency in the U.S.(17) Everyone needs to be mindful about their iron intake. 

The Recommended Dietary Allowance (RDA) for iron is as follows (by age and sex)(17):

Group Age Iron (mg/day)
Infants 0-6 months 0.27*
  7-12 months 11
Children 1-3 years 7
  4-8 years 10
Males 9-13 years 8
  14-18 years 11
  19 and up 8
Females 9-13 years 8
  14-18 years 15
  19-50 years 18
  51-70 years 8
  >70 years 8
Pregnant Women 14-50 years 27
Lactating Women 14-18 years 10
  19-50 years 9

*This value is an Adequate Intake (AI) value. AI is used when there is not enough information known to set a Recommended Dietary Allowance (RDA).

Iron sources

Iron can be found in many plant foods, particularly beans, including:

Food, standard amount(16)(17)(18) Iron (mg)
Soybeans, mature, cooked, 1/2 cup 4.4
Pumpkin and squash seed kernels, roasted, 1 oz 4.2
White beans, canned, 1/2 cup 3.9
Blackstrap molasses, 1 tbsp 3.5
Lentils, cooked, 1/2 cup 3.3
Spinach, cooked from fresh, 1/2 cup 3.2
Amaranth, cooked 1/2 cup 2.6
Kidney beans, cooked, 1/2 cup 2.6
Chickpeas, cooked, 1/2 cup 2.4
Soybeans, green, cooked, 1/2 cup 2.2
Navy beans, cooked, 1/2 cup 2.2
Refried beans, 1/2 cup 2.1
Black beans, cooked, 1/2 cup 1.8
Pinto beans, cooked, 1/2 cup 1.8

Notes on iron

While the form of iron found in plants (non-heme) is absorbed differently than the majority of iron in meat (heme), vegans' intakes can be as high or higher than meat eaters. That said, while a separate Recommended Daily Allowance has not been set for vegans, it is stated that, to compensate for absorption differences, vegans may need to double the RDA for iron while still being careful to avoid overconsuming it. Athletes may also require more iron to make up for their increased activity.(18)

Iron absorption is inhibited when you consume calcium supplements, coffee, and black and green tea at the same time as a foods containing iron. To increase non-heme iron absorption at meals, consume with foods high in vitamin C, such as citrus fruits, bell peppers, and green leafy vegetables.(18) It is widely observed that cooking non-heme foods in a cast iron skillet can improve iron content as well.

What about protein?

Protein contributes to healthy muscles and bones, tissue repair, a healthy immune system, and more(19). Since 10-20% of calories in most plant foods (legumes, vegetables, and grains especially) are from protein(20), and humans need only about 10-15% of their calories from protein, requirements are easily met with a diet consisting of a variety of whole plant foods. Note that it is not necessary to “complement” plant proteins at a meal; the body stores amino acids, the building blocks of protein, so that complete proteins can be manufactured from the diet over the course of the day(21).

The RDA for protein is age and gender dependent. Pregnancy, activity level, and health status also affect your needs(22). However, to get a general sense of what your daily protein intake is in grams, take your weight in pounds and multiply it by .36 (a 150 pound adult would want to consume about 55 grams of protein per day)(23).

The following sample meal plan easily reaches that goal, at 77 grams of protein: 

Breakfast:

1.5 cups oatmeal (9g) + cinnamon combined with
1 oz walnuts (4g)
1 small banana (1g)

Lunch

1.5 cups of three bean chili (16g)
1 piece jalapeño cornbread with maple “butter” spread (2g)
2 cups southwestern vegetable salad (4g)

Dinner:

2 cups stir fried sweet potato, onion, bok choy, and broccoli (5g)
4 oz sesame orange baked tofu (7g)
2 cups brown rice (9g)

Snacks

2 tbsp peanut butter (8g) on whole grain crackers (3g) and fruit (1g)
2 oz trail mix (8g)

Don’t I need some cholesterol?

Though vegan diets are 100% cholesterol free, this is 100% fine. There is no Daily Recommended Intake for cholesterol because it is not an essential nutrient. The body (specifically the liver) manufactures all the cholesterol a person needs to be healthy(24).

What about food allergies?

There are numerous healthy grain alternatives for vegans with a wheat allergy or gluten intolerance. In fact, many grains are nutritionally superior to wheat, including quinoa and millet. Products that were once only available in wheat varieties (such as bread and crackers) are now available wheat- and gluten-free. A soy allergy is also workable; soybeans are just one food. Soy-based meat analogs can be replaced with nut- or wheat-based varieties (such as seitan). Nut allergies are usually isolated; few people are allergic to all nuts and seeds. Testing can determine which nuts and seeds are safe. Substitutions usually work well in recipes and in foods such as granola, trail mix, and nut/seed “butters.”

I tried a vegan diet and felt unhealthy. What did I do wrong?

Sometimes when we make positive changes to our diet—such as eliminating animal products or replacing processed junk food with whole plant foods—we may encounter some temporary bodily complaints, such as cravings, fatigue, or digestive discomfort. These are not uncommon during a major dietary transition, especially if fiber intake increases dramatically in a short period of time. If symptoms continue more than 2-3 days, you may want to see a doctor to rule out coincidental health conditions.

Sometimes a well-intentioned change to eating vegan can backfire when the diet is not properly balanced. One common mistake when transitioning to a vegan diet is eating too few calories. Healthful vegan diets tend to be big on volume–your plate should be overflowing with fresh food, especially when you include lots of raw vegetables. If you continue eating the same volume of food as before, you might not get enough calories, leaving you tired, hungry, and irritable. Another common mistake is simply replacing meat with meat analogs, dairy products with soy alternatives, and regular sweets with vegan sweets; going heavy on these and light on the vegetables, fruits, and whole grains is not a healthy approach. To learn how to best reap the benefits of a healthful vegan diet, sign up for a vegan nutrition or cooking class, or pick up a reliable book on vegan nutrition such as Becoming Vegan, by Brenda Davis and Vesanto Melina.

Too much of a good thing?

Many vegans enjoy some soy products to mimic the flavors and textures of meat and dairy products. Is it possible to consume too much soy? Yes, it is. It’s possible to eat too much of many kinds of foods. Eating too many processed soy products, in particular, means that other foods are being displaced, which throws off a healthful balance of foods. A reasonable daily limit of processed soy products is 2 servings per day, but the healthiest soy products are the least processed and/or those that are fermented: edamame, miso, tempeh, tofu, and fortified soymilk made from whole organic soybeans.

Disclaimer: The information in this guide is intended as a helpful overview but cannot cover all vegan nutrition topics. To make sure that your diet is meeting all the nutrients that your body and mind need, please consult a nutrition professional with expertise in vegan diets.

Produced by The Boston Vegan Association in consultation with Dina Aronson, MS, RD. Subject to revision without notice.

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Demystifying Vegan Nutrition: A Starter Guide by Boston Vegan Association is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License. You may link to this page freely, print for sharing with others, and otherwise reproduce for public education, but you must provide proper accreditation and a link to this page, you may only provide this document to the public free of charge, and you may not modify the contents in any way.

References

(1) Mark J. Messina, “Legumes and soybeans: overview of their nutritional profiles and health effects,” American Journal of Clinical Nutrition, Vol. 70, No. 3, 439S-450S (September 1999).

(2) Harvard School of Public Health, “Health Gains from Whole Grains,” Nutrition Source.

(3) Harvard School of Public Health, “Vegetables and Fruits,” Nutrition Source.

(4) Adel A. Kader, Penelope Perkins-Veazie, and Gene E. Lester, “Nutritional Quality of Fruits, Nuts, and Vegetables and their Importance in Human Health”.

(5) Winston J. Craig, Ann Reed Mangels, “Position of the American Dietetic Association: Vegetarian DietsJournal of the American Dietetic Association, July 2009.

(6) Office of Dietary Supplements, “Dietary Supplement Fact Sheet: Vitamin B12,” National Institutes of Health.

(7) Office of Dietary Supplements, “Dietary Supplement Fact Sheet: Vitamin D,” National Institutes of Health.

(8) “Vitamin D: Boning up on the sunshine vitamin,” CBC News (March 23, 2010).

(11) Office of Dietary Supplements, “Dietary Supplement Fact Sheet: Vitamin D” National Institutes of Health. Also see Brody, Jane E., “What Do You Lack? Probably Vitamin DThe New York Times (2010, July 27) and Nathan Seppa, “Vitamin D Targets IncreasedUS News (2010, November 30).

(12) Holick MF, Brehm, JM, Alcorn, JF, Holguín, F, Aujla, SJ, Celedón, JC (2005). "The Vitamin D Epidemic and its Health Consequences". Journal of Nutrition 135 (11): 2739S–48S. PMID 16251641.

(13) William E. Connor, “Importance of n-3 fatty acids in health and disease,” American Journal of Clinical Nutrition, Vol. 71, No. 1, 171S-175S (January 2000).

(14) Brenda C. Davis and Penny M. Kris-Etherton, “Achieving optimal essential fatty acid status in vegetarians: current knowledge and practical implications: Table 1,” American Journal of Clinical Nutrition, Vol. 78, No. 3, 640S-646S (September 2003).

(15) National Institutes of Health, Office of Dietary Supplements, “Dietary Supplement Fact Sheet: Calcium”.

(16) USDA, National Nutrient Database for Standard Reference (also see individual product labels).

(17) Centers for Disease Control and Prevention, Iron and Iron Deficiency

(18) Office of Dietary Supplements, "Dietary Supplement Fact Sheet: Iron" National Institutes of Health.

(19) National Institute of General Medical Sciences, “Chapter 1: Proteins are the Body's Worker Molecules,” The Structures of Life.

(20) Food and Nutrition Board, Institute of Medicine, “Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids,” Washington, DC: National Academy Press (2002).

(21) Winston J. Craig, Ann Reed Mangels, “Position of the American Dietetic Association: Vegetarian DietsJournal of the American Dietetic Association, July 2009.

(22) World Health Organization, “Protein And Amino Acid Requirements In Human Nutrition”.

(23) Food and Nutrition Board, Institute of Medicine, “Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids,” National Academy Press (Washington, DC, 2002).

(24) Staci Nix, Williams' Basic Nutrition And Diet Therapy (St. Louis, MO: Elsevier Mosby, 2005), p. 33.

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