Health Care Quarterly:

Planting the seeds for a successful vegan diet

Thu, May 23, 2019 (2 a.m.)

People who choose to eliminate meat from their diet may do it for many reasons — compassion towards animals, environmental concerns, a lower risk of chronic diseases — or to manage those diseases.

Although it may sound limiting, a well-rounded vegan diet containing vegetables, fruits, whole grains, legumes, nuts and seeds can provide adequate nutrition. There may be fewer nutrients due to a lack of animal foods/products, but deficiencies can be avoided. The Academy of Nutrition and Dietetics says that appropriately planned vegetarian diets, including veganism, are healthful, nutritious, and may offer health benefits for the prevention and treatment of certain disease.

When it comes to the potential nutrient deficiencies, special attention needs to be paid to protein, iron, zinc, calcium, vitamin D, fatty acids and vitamin B12, among others.

Protein needs vary throughout life but a mild deficiency can result in muscle wasting, an inability to increase lean muscle mass, decreased immunity, bone loss, hair loss, brittle nails, weight gain and inadequate oxygenation to tissues.

Adequate protein intake isn’t a mere matter of getting enough; proteins need to be broken down into amino acids before they can be used by the body. That takes certain enzymes but plants contain several compounds that inhibit those enzymes, meaning that a vegan’s body may not be getting all the protein it needs. Sometimes the process is a mere matter of digestibility; soaking or sprouting your nuts, seeds, legumes, and grains can help.

Speaking of amino acids, don’t forget about them when planning a vegan diet. Nine are considered essential because they are not produced by the body: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine. Non-essential amino acids (those that are produced by the body) may be needed in increased amounts during times of stress. These include arginine, cysteine, glutamine, glycine, proline, taurine and tyrosine.

Be aware that all plant proteins are low in methionine, leucine, lysine and tryptophan. That can be helped with soy, dry beans, peas, nuts, seeds, whole grains and cruciferous vegetables.

All nine essential amino acids can be found in soy, amaranth, buckwheat, quinoa, hemp seeds and chia seeds.

Iron may be an issue for children, teens, women of childbearing age, and pregnant women who follow a vegan diet. Plant-based foods contain non-heme iron, a form that is not as well absorbed as heme iron, the form found in meat and other sources from animal origins. In addition, beans, nuts, seeds and grains contain phytates, compounds that are significant inhibitors of iron absorption. You can improve the absorption of non-heme iron by including fruit juice, broccoli or bell peppers, which are a great source of vitamin C.

Zinc, a mineral essential for many body processes, may come up short in vegetarian and vegan diets. As with iron, many plant-based foods contain zinc, but its bioavailability is less than that of animal-based foods. By eating whole-grain foods, different types of beans and peas, fortified breakfast cereals, seeds and nuts, you can reach zinc goals. Focus on whole-grain bread and pasta because zinc is lost when processing grains to make refined flour. Speaking of bread, phytates can inhibit zinc absorption but get broken down when yeast fermentation is used to make dough rise.

Know that supplementing a diet with zinc is potentially harmful as doses can be high and can disrupt the balance of iron and copper.

Calcium intake among vegans can vary widely; some low-dose supplementation may be required. Foods that provide a more adequate source of calcium are tofu and tempeh processed with calcium, calcium-fortified soy or rice beverages, broccoli, almonds, soybeans, some greens (kale, collards, mustard greens, turnip greens), okra, bok choy and figs.

Vitamin D status depends on sunlight exposure and the intake of vitamin D-fortified foods or supplements. The most common method of getting vitamin D in the diet is by consuming fortified milk and milk products. For vegans, because dairy is eliminated, another source of vitamin D (which helps absorb calcium) is required. Look at a food’s nutrition facts to see its vitamin D content. Some breakfast cereals; plant-based beverages such as soy, rice, almond, and hemp; cereal bars, and calcium-fortified juices are also fortified with vitamin D — though it is often the inactive vitamin D2 which the body must convert to vitamin D3. Mushrooms that are treated with ultraviolet light can be a significant source of vitamin D. If sunlight exposure and intake of fortified foods is inadequate to meet recommended needs, then a vitamin D3 supplement is recommended, especially for older adults.

Essential fatty acids are called such because the body cannot produce them; they are an essential part of the diet. People following a vegan diet may be lacking some fatty acids, although not necessarily and the clinical relevance of the reduction among vegetarians and vegans is unknown. Good plant sources of omega-3 fatty acids are seeds (flax, chia, camelina, canola and hemp), walnuts and their oils.

Vitamin B-12 is abundant in foods of animal origin. Vegans must regularly consume foods fortified with B-12 or take supplements. People with little or no intake of B-12 may feel healthy; however long-term deficiency can lead to stroke, dementia and poor bone health.

 

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With research, planning and dedication, a vegan diet can provide the required nutrition one needs. Focus on whole foods and make sure to eat a wide variety of foods on a daily basis to maintain an adequate nutritional intake. If you decide to eliminate animal products and feel that your diet may have deficiencies, seek advice from your doctor or registered dietitian before taking supplements. Adding more plants into our diet is for the best, and as registered dietitians we encourage everyone to explore their diet and see how incorporating more plants will work best for them.

Kristina LaBouff and Collette Sinnott are registered dieticians with MountainView Hospital.

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