Food As Prevention

Avoiding chronic disease through a healthy diet

Supplements

By this point I hope that you are convinced that the healthiest diet is composed of whole foods, is plant-based, low in fat, and low in processed foods.

While no diet can guarantee to supply all of your nutritional requirements the American Academy of Nutrition and Dietetics has stated that “vegan diets are healthful, nutritionally adequate and may provide health benefits including reduced risk of ischemic heart disease, type 2 diabetes, hypertension, certain types of cancer, and obesity . . . Vegans need reliable sources of vitamin B-12 such as fortified foods or supplements”.  Their full position statement has excellent information on supplements.

Here is a nice video by a dietician which covers vitamins B12 and D, omega 3, zinc and iron (9 min):

If you decide to follow this diet you need to know the following about vitamins and supplements:

Vitamin B12

Vitamin B12 is important in the function of the nervous system and the making of blood.  Deficiency can be associated with anemia, and nerve damage which can be irreversible. Both the American and Ontario governments state that the daily requirement for vitamin B12  for adults is 2.4 micrograms (mcg) per day.  This will not be supplied reliably with a diet that does not contain animal products and supplementation is necessary. Supplementation with 1000 mcg (1 mg) of vitamin B12 per day should be adequate (1); however I also suggest that you have your vitamin B12 level checked annually.  Further reading here.

Omega 3

While it is not difficult to obtain adequate amounts of alpha-linoleic acid (ALA) in a vegan diet (eg chia seeds, flax seeds, hemp seeds), it can be difficult to get enough eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).  Supplementation with a combination of DHA and EPA supplying 250 mg of DHA + EPA per day (2,5) should be adequate as shown in this excellent 6 min video.  Since fish-oil derived products are often contaminated, a pollutant free source (eg from algae) is preferable.  Learn more about omega 3 here.

Vitamin D

While considered important for bone health, the role of vitamin D in other health conditions is highly controversial (3).  It is quite common for both vegans and up to 40% of non-vegans to be deficient (4). Current North American Guidelines are for 600 IU/day for adults 18-70 years and 800 IU per day for adults > 70 years with a tolerable upper intake of 4000 IU per day.  In my experience, the intake of 600-800 IU per day will result in a degree of deficiency for many adults.  I would suggest at least 1000 IU per day (especially if you have a dark skin color) and considering 2000 IU per day in winter (for Canadians) which is consistent with the guidelines by Osteoporosis Canada.  Since there is theoretical toxicity with too much vitamin D, you should have your level checked from time to time by your doctor.  Nice article on this here.

In addition if you don’t eat iodized salt (or if you avoid adding salt), you should supplement with 150 mcg (micrograms) of iodine per day or regularly eat algae which is a vegan source of iodine. This is important (see here & here).

Thus to summarize, people consuming an exclusively plant-based diet need to be aware of the need to make sure they are getting all their nutrients.  Here is an excellent study/article by Dr Klaper where he shares his findings on 45 vegans who he assessed for ‘failure to thrive’ with his practical recommendations.

Further Reading on Nutritional Concerns with a plant-based Diet:

  1. Healthy Eating Guidelines for Vegans – Dieticians of Canada
  2. Guide to Vegan Eating – Dieticians Association of Australia
  3. Nutrients that Need Attention in Vegan Diets – Jack Norris Rd.
  4. How to reliably get zinc on a vegan Diet – iNourishGently.
  5. Lovely chart of best vegan sources of protein / calcium / iron / zinc / omega 3 here.

Next step: Learn about conventional vs organic produce

References

  1. Becoming Vegan – Comprehensive Edition.  B Davis and V Melina. Book Publishing Company, Summertown, TN 2014.  Pages 214-222.
  2. Ibid. pp 107-146.
  3. Vitamin D: A Narrative Review Examining the Evidence for Ten Beliefs.  GM Allan et al.  J General Internal Medicine 2016:31(7):780-91.
  4. Prevalence and correlates of vitamin D deficiency in US adults.  KYZ Forrest, WL Stuhldreher. Nutrition Research 2011:31:48-54.
  5. Toward Establishing Dietary Reference Intakes for Eicosapentanoic and Docosahexanoic Acids.  WS Harris et al. J Nutrition 2009:139:804S-819S.
  6. Effect of the Vegetarian Diet on non-communicable Diseases. D Li. J Sci Food Agric 2014:94(2):169-173.