The 4 Nutritional Shortfalls Of A Vegan Diet And How To Combat Them

4 Actionable Steps To Combatting The Main Nutritional Shortfalls Of A Vegan Diet

A plant-based diet comes together with a plethora of health benefits, as it is usually high in fiber, folic acid, vitamins C and E, potassium, magnesium, and many phytochemicals and a fat content that is more unsaturated. On the other hand, in comparison with vegetarian diets, vegan diets tend to contain less saturated fat and cholesterol and more dietary fiber. Vegans tend to be thinner, have lower serum cholesterol, and lower blood pressure, reducing their risk of heart disease.

This being said, we should not underestimate the fact that adopting a vegan diet can still pose a challenge in terms of meeting the body’s nutritional needs. Among the large amount of propaganda nowadays, it is very easy to miss out on the essentials – HOW to adopt a vegan diet in a safe, healthy, educated way. Denying the nutritional pitfalls of plant-based eating by no means makes us more of a ‘vegan’ – it simply makes us bad advocates of plant-based eating. Micronutrients of special concern for the vegan include vitamins B-12 and D, and long-chain n–3 (omega-3) fatty acids.

The purpose of this article is to summarize the possible nutritional concerns that a vegan might face, and provide a solution to them. It by no means aims to discredit veganism or make it look ‘too hard’ to adopt.

The scientific findings and conclusions have been taken from this peer-reviewed review article that summarizes the studies that have looked at the health effects of a vegan diet.

The 4 Nutritional Shortfalls Of A Vegan Diet And How To Combat Them

1. Vitamin B-12

The 4 Nutritional Shortfalls Of A Vegan Diet And How To Combat Them

Compared with lactoovovegetarians and omnivores, vegans typically have lower plasma vitamin B-12 concentrations, higher prevalence of vitamin B-12 deficiency, and higher concentrations of plasma homocysteine. Elevated homocysteine has been considered a risk factor for CVD and osteoporotic bone fractures. Vitamin B-12 deficiency can produce abnormal neurologic and psychiatric symptoms that include ataxia, psychoses, paresthesia, disorientation, dementia, mood and motor disturbances, and difficulty with concentration. In addition, children may experience apathy and failure to thrive, and macrocytic anemia is a common feature at all ages.

Solution

To avoid B-12 deficiency, vegans should regularly consume vitamin B-12–fortified foods, such as fortified soy and rice beverages, certain breakfast cereals and meat analogs, and B-12–fortified nutritional yeast, or take a daily vitamin B-12 supplement. Fermented soy products, leafy vegetables, and seaweed cannot be considered a reliable source of active vitamin B-12. No unfortified plant food contains any significant amount of active vitamin B-12.

2. Vitamin D

The 4 Nutritional Shortfalls Of A Vegan Diet And How To Combat Them

In the EPIC-Oxford study, vegans had the lowest mean intake of vitamin D (0.88 μg/d), a value one-fourth the mean intake of omnivores. For a vegan, vitamin D status depends on both sun exposure and the intake of vitamin D-fortified foods. Those living in areas of the world without fortified foods would need to consume a vitamin D supplement. Living at high latitudes can also affect one’s vitamin D status, because sun exposure in that region is inadequate for several months of the year. Those who are dark skinned, elderly, who extensively cover their body with clothing for cultural reasons, and who commonly use sunscreen are at an increased risk of vitamin D deficiency. Another matter of concern for vegans is that vitamin D2, the form of vitamin D acceptable to vegans, is substantially less bioavailable than the animal-derived vitamin D3.

Solution

To ensure an adequate vitamin D status, especially during the winter, vegans must regularly consume vitamin D–fortified foods such as soy milk, rice milk, orange juice, breakfast cereals, and margarines that are fortified with vitamin D. Where fortified foods are unavailable, a daily supplement of 5–10 μg vitamin D would be necessary. The supplement would be highly desirable for elderly vegans.

3. n–3 Polyunsaturated fat

The 4 Nutritional Shortfalls Of A Vegan Diet And How To Combat Them

Diets that do not include fish, eggs, or sea vegetables (seaweeds) generally lack the long-chain n–3 fatty acids, eicosapentaenoic acid (EPA; 20:5n−3) and docosahexaenoic acid (DHA; 22:6n−3), which are important for cardiovascular health as well as eye and brain functions. The plant-based n–3 fatty acid α-linolenic acid (ALA; 18:3n−3) can be converted into EPA and DHA, albeit with a fairly low efficiency. Compared with nonvegetarians, vegetarians, and especially vegans, tend to have lower blood concentrations of EPA and DHA. However, vegans can obtain DHA from microalgae supplements containing DHA, as well as from foods fortified with DHA. However, EPA can be obtained from the retroconversion of DHA in the body. The oil from brown algae (kelp) has also been identified as a good source of EPA.

Solution

A vegan should regularly consume plant foods naturally rich in the n–3 fatty acid ALA, such as ground flaxseed, walnuts, canola oil, soy products, and hemp seed–based beverages. In addition, it is recommended that vegans consume foods that are fortified with the long-chain n–3 fatty acid DHA, such as some soy milks and cereal bars. Those with increased requirements of long-chain n–3 fatty acids, such as pregnant and lactating women, would benefit from using DHA-rich microalgae supplements.

4. Zinc

The 4 Nutritional Shortfalls Of A Vegan Diet And How To Combat Them

Vegetarians are often considered to be at risk for zinc deficiency. Phytates, a common component of grains, seeds, and legumes, binds zinc and thereby decreases its bioavailability. However, a sensitive marker to measure zinc status in humans has not been well established, and the effects of marginal zinc intakes are poorly understood. Although vegans have lower zinc intake than omnivores, they do not differ from the nonvegetarians in functional immunocompetence as assessed by natural killer cell cytotoxic activity. It appears that there may be facilitators of zinc absorption and compensatory mechanisms to help vegetarians adapt to a lower intake of zinc.

Solution

Because of the high phytate content of a typical vegan diet, it is important that a vegan consume foods that are rich in zinc, such as whole grains, legumes, and soy products, to provide a sufficient zinc intake. Benefit could also be obtained by vegans consuming fortified ready-to-eat cereals and other zinc-fortified foods.

Studies mentioned

Majchrzak D, Singer I, Manner M, et al. B-vitamin status and concentrations of homocysteine in Austrian omnivores, vegetarians and vegans. Ann Nutr Metab2006;50:485–91

McNulty H, Pentieva K, Hoey L, Ward M. Homocysteine, B-vitamins and CVD.Proc Nutr Soc 2008;67:232–7.

McLean RR, Jacques PF, Selhub J, et al. Plasma B vitamins, homocysteine and their relation with bone loss and hip fracture in elderly men and women. J Clin Endocrinol Metab 2008;93:2206–12.

Food and Nutrition Board, Institute of Medicine. Vitamin B12: Dietary Reference Intakes for thiamin, riboflavin, niacin, vitamin B6, folate, vitamin B12, pantothenic acid. Washington, DC: Biotin, and Choline. National Academy Press,1998;306–56

Burdge GC, Finnegan YE, Minihane ME, Williams CM, Wootton SA. Effect of altered dietary n–3 fatty acid intake upon plasma lipid fatty acid composition, conversion of [13C]alpha-linolenic acid to longer-chain fatty acids and partitioning towards beta-oxidation in older men. Br J Nutr 2003;90:311–21.

Burdge GC, Wootton SA. Conversion of alpha-linolenic acid to eicosapentaenoic, docosapentaenoic and docosahexaenoic acids in young women. Br J Nutr 2002;88:411–20.

Rosell MS, Lloyd-Wright Z, Appleby PN, Sanders TAB, Allen NE, Key TJ.Long-chain n−3 polyunsaturated fatty acids in plasma in British meat-eating, vegetarian, and vegan men. Am J Clin Nutr 2005;82:327–34.

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