The vegan diet has gained momentum in recent years, with more people transitioning to the diet, whether for health or more ethical-based reasons. It’s often characterized as very restrictive, is associated with health benefits but also raises concerns. Controversy regarding the diet exists within the public sphere, with those actively supporting and advocating for it, and others questioning its purpose and proposed benefits, perhaps because of a lack of knowledge about the diet.

1. The vegan
diet and its
implication

2. The vegan diet has gained momentum in recent years, with more people transitioning to the diet,
whether for health or more ethical-based reasons. It’s often characterized as very restrictive, is
associated with health benefits but also raises concerns.
Controversy regarding the diet exists within the public sphere, with those actively supporting and
advocating for it, and others questioning its purpose and proposed benefits, perhaps because of a
lack of knowledge about the diet.
The vegan diet is defined as one that includes only plant foods, namely, grains, vegetables, fruits,
legumes, nuts, seeds, and vegetable fats.
It is described as a restrictive diet as it excludes meat, fish, and its products which are abundant
sources of protein, essential vitamins, and minerals.
Nutrients of particular concern in a vegan diet include protein, calcium, vitamin D, vitamin B-12,
riboflavin, zinc, iron, fiber, as well as fat and essential fatty acids.

3. Protein
Dietary protein sources in the vegan diet are plant-based proteins. Interestingly, on a global
basis, plants provide about 65% of the world’s supply of edible protein. Such products include
soymilk, tofu, tempeh, seitan, legumes, grains, nuts, and seeds.
But, the dietary protein from plant foods is only about 85% digestible. To counter the effects of
the lower digestibility of plant proteins, the Recommended Dietary Allowances (RDA) suggests
increasing daily recommendations for vegans by 10 to 15%.

4. Calcium
Vegans can easily meet the daily requirements without supplementation through the
consumption of both vegetables and calcium-fortified non-dairy milk.
Non-dairy milk/yogurt averages 200-300 mg/cup while cooking green leafy vegetables increases
the calcium bioavailability from anywhere between 30-70 mg/cup to 200-350 mg/cup depending
on the green (collard leaves – 2350 mg/cup, turnip greens 250 mg/cup.
However, if vegan diets are unvaried, especially in children, it is advisable to consume calcium
supplements between meals under guidance.

5. Vitamin D
Vitamin D, an essential nutrient, is both produced in the body by sunlight exposure and found in
smaller quantities within foods.
However, vitamin D is limited in non-fortified foods, with the best sources being fortified
products, in particular, fortified dairy milk.
For vegans, vitamin D fortified foods include soymilk, rice milk, and breakfast cereal. On
average, adequate vitamin D is obtained both by sun exposure and consumption of fortified
foods in both vegans and in non-vegans.

6. Vitamin B-12
Vitamin B-12 is mostly obtained in animal-derived food; it is often classified as a nutrient that
both vegetarians and vegans lack.
However, this issue should not be of concern if eating a varied diet of fortified foods. Similar to
vitamin D, the best source of vitamin B-12 is fortified food.
Adequate vitamin B-12 can be achieved by consuming fortified foods such as breakfast cereals,
soy beverages, nutritional yeast, and meat analogs. Those that are unfortified are unreliable
sources

7. Zinc
Zinc, an essential mineral, is found in similar densities in vegan, omnivorous, and vegetarian
diets. Yet, certain concern exists due to the reduced bioavailability of zinc in plant sources.
While vegans consume zinc via legumes, whole grain pasta, wheat germ, fortified cereals, nuts,
and tofu, the bioavailability of zinc from plant foods is reduced by phytate in whole grains and
legumes. Phytate, bind with minerals, preventing mineral (zinc) absorption.
It’s evident that vegetarians have lower levels of total zinc and plasma zinc concentrations,
although most often in acceptable ranges. This is due to lower zinc intake and absorption.
However, it is observed that over time, there is an adaptation by decreased zinc excretion when
dietary zinc is low.

8. Iron
Iron consumption is often a concern in vegetarian and vegan diets. The two different forms of
dietary iron, are heme and non-heme.
While non-heme iron is found in plant foods, heme iron is only found in animal foods that
originally contained hemoglobin, and in general absorption of non-heme iron is lower than heme
iron.

9. Iron
Although on average, iron intake appears at or above the RDA recommended daily levels, due
to the lower absorbability of non-heme iron, vegetarians have lower iron stores.
A higher percentage of individuals have stores below the normal range. It’s well known that low
levels of iron cause iron deficiency anemia. But the studies have stated that
“Vegans/vegetarians have no higher rates of anemia than those seen, in the general
population.”
This could be because, absorption of non-heme iron is greatly enhanced by vitamin C and other
organic acids found in vegetables and fruits, both significant components of vegetarian and
vegan diets

10. Iron
However, lower levels of iron are detected in vegans, which may be explained by the
composition of the vegan diet.
Once again, increased levels of phytates in vegan diets decrease the absorption of minerals,
such as iron. Studies have suggested adaptive regulatory response in vegans which allows for
increased absorption of iron.
That is, for vegans, ascorbic acid and other dietary factors can promote iron absorption even in
the presence of phytates, increasing the once lower levels of iron in vegetarians and vegans.

11. Fiber
Fiber is a necessary part of every diet. Dietary fiber is a type of indigestible carbohydrate and is
either soluble or insoluble.
While soluble fiber attracts water and slows digestion, insoluble fiber helps food to pass more
quickly through the digestive system from the stomach into the intestines.
Studies have shown fiber intake to be higher in vegans in comparison to omnivores and
vegetarians, even exceeding daily recommendations.
High fiber intake is generally believed to result in more favorable lipid profiles and lower
triglyceride levels

12. Fat and essential fatty acids
It’s ideal to obtain about 25 – 30% of energy in the regular diet from fat, including both fats and
essential fatty acids. Here, the particular concern is long-chain omega-3 fatty acids, namely
docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA).
While vegan diet fats rely on nuts, seeds, avocado, soy products, and vegetables to meet their
energy and nutrient needs, they lack in DHA and EPA. While the linoleic acid found in seeds
can be converted to EPA and DHA, its efficiency of conversion is reduced in diets high in the
omega-6 fatty acid linoleic acid, of which vegan diets seem to have a high amount.

13. Fat and essential fatty acids
Thus intake of essential fatty acids should be taken into greater consideration in the vegan diet,
as they are essential to cardiovascular health, and brain and eye functions. Lowering the
amount of omega-6 fatty acid, linoleic acid, will increase the efficiency of conversion of linolenic
acid to both DHA and EPA
Currently, there are no known risks for diets low in long-chain omega-3 fatty acids, although an
increase in such to obtain a more desirable ratio of omega-6 to omega-3 fatty acids is beneficial.

14. Fat and essential fatty acids
Overall, the key to a nutritionally sound vegan diet is variety. A healthy and varied vegan diet
includes fruits, vegetables, plenty of leafy greens, whole grain products, nuts, seeds, and
legumes in the right proportion and portion.
Nutrients intake discussed above, are the specific nutrients of concern in vegan diets. Greater
attention to the intake of these nutrients should be given, therefore guidance of a certified
nutritionist is needed to understand where your diet might be lacking, and how to overcome it in
the right way.
Well-Planned vegan diets are regarded as appropriate for all stages of life, including infancy and
pregnancy,

15. Fat and essential fatty acids
Vegan diets have been shown to lower the risk of type 2 diabetes, high blood pressure, obesity,
and ischemic heart disease.
It tends to be lower in some micronutrients thus, as with a poorly-planned diet of any other
variation, an unbalanced vegan diet may lead to nutritional deficiencies that nullify any beneficial
effects and may cause serious health issues

16. THANK YOU
Originally published at https://www.quanutrition.com on March 26, 2022.