Your Guide to Vegetarian and Vegan Nutrition and Possible Deficiencies
If you’re interested in starting a strict, plant-based diet (vegetarian or vegan) or currently follow one, please take the time to read through the information on this page.
Most people assume that a vegetarian or vegan diet is a healthy one. And it can be if you get enough zinc, vitamin B12, omega-3 DHA, and omega EPA, which is more complicated on a strict, plant-based diet.
Omega-3 DHA and EPA fatty acids
Most people are familiar with omega-3 fatty acids and their health benefits. The body can’t make these fatty acids, so you have to get them from food.
There are three types. Omega-3 DHA, EPA, and ALA. You need DHA and EPA for your heart, memory, focus, and eyes. Foods high in omega-3 DHA can also slow down brain aging. It helps make the myelin (the insulation around the nerves) stronger, so nerve impulses travel faster.
Unfortunately, you can only get DHA and EPA from fish or a fish oil supplement. The good news is, your body can convert omega-3 ALA to a small percent of DHA.
But, there’s another reason to consume ALA-rich foods. ALA promotes liver restoration, slows the aging process, and converts glucose to energy.
Best sources of Omega-3 ALA
The foods with the highest amounts of omega-3 ALA are chia seeds, flaxseeds, and walnuts. Since they’re higher in ALA, you’ll get more converted to omega-3 DHA.
Zinc is an essential trace mineral. Your body needs it to grow, develop, and heal wounds. Your immune and reproduction systems, neurological function, and sense of taste also rely on it. Unfortunately, only red meat and shellfish have sufficient amounts.
Most multivitamin and mineral supplements have all the zinc you need. If you don’t take a multi, there are zinc supplements. Another option is to eat foods that are fortified with it.
How much zinc do you need?
The Recommended Dietary Allowance (RDA) is 8 mg. a day for women and 11 mg. a day for men. But for strict vegetarians, the daily requirement is 50% higher. ¹
That’s because vegetarians eat a lot of fiber, grains, and legumes. These foods have phytic acid, and phytic acid interferes with zinc absorption. ²
Tip: The enzymatic action of yeast reduces the level of phytic acid in foods. So, leavened, whole grain bread has more bioavailable zinc (zinc that your body can use) than unleavened, whole grain bread.
There are some techniques you can use to increase the amount of zinc your body absorbs by using the following methods: ³
- Sprouting (to germinate lentils, mung beans, seeds, nuts, or grains)
- Soaking ( to prepare for cooking)
- Yeasting ( to make bread)
- Fermenting (to make sourdough bread and tempeh)
- Roasting (to toast nuts)
Best sources of vegan and vegetarian zinc
You can get small amounts of zinc from plant foods. These are the best sources:
|Crimini mushrooms (5 oz.)||1.56 mg|
|Spinach (1 cup)||1.37 mg|
|Pumpkin seeds (1/4 cup)||2.57 mg|
|Sesame seeds (1/4 cup)||2.8 mg|
|Cashews, dry roasted (1 ounce)||1.6 mg|
|Bran Flakes (1 cup)||2.0 mg|
|Wheat Germ (2 tablespoons)||2.7 mg|
|Adzuki Beans||2 mg|
Potential Vitamin B12 deficiency for Vegans and Vegetarians
Vitamin B12 is a water-soluble vitamin. It’s needed to make DNA and RNA and to maintain healthy nerve cells. B-12 also works with other B vitamins to make red blood cells and produce S-adenosylmethionine (SAM-e). Your body needs SAM-e for a healthy immune system and mood).
How much B-12 do you need?
The only good sources of vitamin B12 are meat and fish. So vegetarians and vegans have to rely on fortified foods and supplements. Studies show that both do an excellent job in preventing deficiencies.4
The RDA is only 2.9 mcg (1 mcg, or microgram = 1,000 mg) for adults over 19. If pregnant, 2.6 mcg, or lactating, 2.8 mcg. The Daily Value (DV) is 6 mcg.
Keep in mind that there are absorption issues with B-12. The older you get, the less your body can absorb. If you have digestive problems, they can also interfere with absorption.
Recommended Dietary Allowance (RDA) and Daily Value (DV) Explained
The RDA is the average, daily dietary nutrient amount sufficient to meet the nutrient requirements of nearly all (97 to 98 percent) healthy individuals in a particular life stage and gender group.¹
Dietary Reference Intakes (DRIs) are expanding and replacing the RDAs.
Daily Values were developed to serve as a reference to help consumers use the information on food labels to plan an overall healthy diet. The DV is based on expert dietary advice about how much, or how little, of some key nutrients you should eat each day, depending on whether you eat 2,000 or 2,500 calories a day.²
1 National Academy of Sciences., Dietary Reference Intakes: The Essential Guide to Nutrient Requirements
2 U.S. Food and Drug Administration (1999)
Why You Need 1.8% More Iron Than Meat Eaters
Iron is an essential mineral needed to carry oxygen throughout the body. Your body also needs it for cognitive development, temperature regulation, immune health, and energy metabolism.
For non-vegetarians/vegans, the recommended Daily Value (DV) is 18 mg. The RDA is 8 mg for men and women over 50. And 18 mg for women who are between 19 and 50 years old.
Iron is not as easily absorbed from plant sources as it is from animal sources. So, the recommended amount for vegetarians and vegans is 1.8 times higher.
What are the best sources of iron?
The best sources are animal proteins, but you can get some iron from cooked soybeans, lentils, oatmeal, cooked spinach, and whole-grain bread and pasta.
To stay healthy on a vegan or vegetarian diet, focus on a well-balanced diet that compensates for the potential lack of nutrients covered in this article. If, for any reason, this is difficult for you, consider a plant-based diet that includes some animal protein.
1 Dietary Reference Intakes: The Essential Guide to Nutrient Requirements, Jennifer J. Otten, Jennifer Pitzi Hellwig, Linda D. Meyers, Editors, National Academy of Sciences
2 Prasad, A. S. (2003), “Zinc deficiency”, British Medical Journal 326 (7386): 409, doi:10.1136/bmj.326.7386.409, PMC 1125304, PMID 12595353
3 Brenda Davis, Vesanto Melina, Becoming Vegan: the complete guide to adopting a healthy plant-based diet.
4 Katherine L Tucker, Sharron Rich, Irwin Rosenberg, Paul Jacques, Gerard Dallal, Peter WF Wilson and Jacob Selhub, “Plasma vitamin B12 concentrations relate to intake source in the Framingham Offspring Study,” American Journal of Clinical Nutrition, Vol. 71, No. 2, 514-522, February 2000.
The World’s Healthiest Foods, Fact Sheet: Omega-3 Fatty Acids
Goyens PLL, Spilker ME, Zock PL, et al., “Conversion of α-linolenic acid in humans is influenced by the absolute amounts of α-linolenic acid and linoleic acid in the diet and not by their ratio,” Am. J. Clin. Nutr. , 2006
Burdge GC, Calder PC, “Conversion of α-linolenic acid to longer-chain polyunsaturated fatty acids in human adults,” Reprod. Nutr. Dev.
Burdge GC, Wootton SA., “Conversion of α-linolenic acid to eicosapentaenoic, docosapentaenoic and docosahexaenoic acids in young women, ” Br. J. Nutr., 2002. Nutr. , 2006
NIH Clinical Center website
Paul Pitchford, Healing with Whole Foods; Asian traditions and modern nutrition.
Dietary Reference Intakes: The Essential Guide to Nutrient Requirements
Brent Agin and Sharon Perkins, Healthy Aging for Dummies
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Disclaimer: The information on this site is for information purposes only. It is not intended to replace your healthcare professional or provide diagnosis or treatment.