YOGA & NUTRITION. What we need to know about vegetarian diets.

Let’s continue our conversation about vegetarian diets. A little reminder: the Academy of Nutrition and Dietetics consider vegetarian diets healthy as they are often associated with low cholesterol levels, lower risk of heart disease, lower blood pressure, and subsequently lower risk of hypertension and Type II diabetes.  This is a good start! Many people are concerned with inadequate intake of protein when switching to vegetarian or vegan diets. Research shows that lacto-ovo-vegetarians should not worry, as their daily protein intake seems to meet and, in some cases, exceed the Recommended Dietary Allowance (RDA) (Messina, Mangels, & Messina, 2004). However, vegans should eat more beans and soy protein as they are rich in lysine – an essential amino acid. What about micronutrients?

Iron
This micronutrient might be problematic in vegetarian diets because iron in plants exists in its nonheme (non-bound or free) form.  This means that several elements such as phytates, calcium, and polyphenols existing in teas, coffee, and herbs can easily block iron absorption.  Conversely, vitamin C and some processing techniques such as leavening bread and fermentation can enhance iron absorption.

Zinc
Phytic acids found in grains tend to inhibit absorption of zinc. The best way to prevent this is to ‘let the bread rise’. Literally! People on strict raw food diets may be zinc-deficient. Great sources are soaked and sprouted beans, soy products, legumes, cheese and nuts.

Iodine
Iodine is important for a healthy thyroid. Most people receive their RDA of iodine from iodized salt; however, vegetarians who use kosher and sea salt should be aware - these salts do not contain iodine. Soybeans, cruciferous vegetables (broccoli, cabbage, cauliflower), and sweet potatoes are all great sources of natural goitrogens which will help to keep our thyroid in check.

Calcium
Vegan diets tend to be low in calcium. The EPIC-Oxford study found that vegans have 30% higher risk of bone fracture compared to lacto-ovo-vegetarians or meat eaters (Appleby, Roddam, Allen, & Key, 2007). Some may argue that spinach and Swiss chard are good sources of calcium, and indeed they are; however, the presence of oxalic acid in these vegetables reduces calcium absorption to as low as 5%. Low-oxalate greens like bok choy, broccoli, Chinese cabbage, collards and kale are much better options. Fruit juices, soy and rice milk, and breakfast cereals fortified with calcium are also great sources.

Vitamin D
There is no better source of vitamin D than our own body – yes, it is of animal origin! All we need to do is to be exposed to sunlight for at least 15 minutes every day. If you leave in Seattle – vitamin D supplements and fortified soy milk could be an alternative.

Vitamin B-12
You would be hard pressed to find a plant food which could be an adequate source of vitamin B-12 – because none exists. While lacto-ovo-vegetarians can obtain B-12 from dairy foods and eggs, vegans are in trouble. To make matters worse, the symptoms of vitamin B-12 deficiency could be masked by a vegetarian diet rich in folate. Consuming B-12-fortified foods and taking supplements is the only option.

General advice to those who decide to switch to vegetarian or vegan diets: KNOW YOUR FOODS AND UNDERSTAND HOW NUTRIENTS ARE ABSORBED!

References:

Appleby, P., Roddam, A., Allen, N., & Key, T. (2007). Comparative Fracturein Vegetarians and Nonvegetarians in EPIC-Oxford. Eur J Clin Nutr, 61, 1400 - 1406.

Messina, V., Mangels, R., & Messina, M. (2004). The Dietician's Guide to Vegetarian Diets: Issues and Applications, 2nd ed. Sudsbury, MA: Jones and Barlett Publishers.

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