March 19, 2013

Vegan Diet: Pros and Cons

Yesterday I posted two videos produced by Dr. Michael Greger, an internationally recognized expert on nutrition and food safety, that made a case for the vegan diet for both treating and forestalling Parkinson's. After doing some additional research, I've decided to give the vegan diet a try for the next month.

Here's a synopsis on my research on vegan diet pros and cons:

The Academy of Nutrition and Dietetics concludes that "well-planned" vegetarian and even vegan diets are "healthful, nutritionally adequate, and may provide health benefits in the prevention and treatment of diseases like type 2 diabetics, obesity, heart disease, and cancer.

Weight loss: Research shows vegans tend to eat fewer calories, weigh less, and have a lower body mass index (a measure of body fat) than their meat-eating counterparts. In one study, 99 participants with type 2 diabetes followed either a vegan diet or a diet based on American Diabetes Association guidelines. After 22 weeks, the vegans lost an average of 13 pounds vs. 9 in the ADA group, according to findings published in 2006 in Diabetes Care.

Cardiovascular benefits:
In the 2006 Diabetes Care study mentioned above, researchers concluded that vegan diets have a lipid- and cholesterol-lowering effect, likely because they eliminate dietary cholesterol (plant products are cholesterol-free) and are low in saturated fat. The soluble fiber found in plant-protein also helps to lower cholesterol, according to the report. After 22 weeks, LDL cholesterol dropped 21.2 percent in the vegan group, compared with 10.7 percent in the group following American Diabetes Association guidelines. Triglycerides fell from 140.3 mg/dL to 118.2—which is important, because high triglycerides can jeopardize heart health. And systolic blood pressure dropped from a borderline-high 123.8 to 120, while diastolic fell from a normal 77.9 to an even lower 72.8.

Bill Clinton:  Former president Bill Clinton switched to a vegan diet in 2011 and lost 24 pounds in a few months. He credits the diet with saving his life. He looked great campaigning last fall. He says he has much more energy now and, at 185 pounds, is the same weight he was at age 13.

The primary concern about a vegan diet is that it may lead to an increased risk of deficiencies of vitamin B12, vitamin B2, calcium, iron, and zinc. The Mayo Clinic says, however, that with a  little care and attention these concerns can be alleviated.  Here's its advice:
  • Calcium helps build and maintain strong teeth and bones. Milk and dairy foods are highest in calcium. However, dark green vegetables, such as turnip and collard greens, kale and broccoli, are good plant sources when eaten in sufficient quantities. Calcium-enriched and fortified products, including juices, cereals, soy milk, soy yogurt and tofu, are other options.
  • Iodine is a component in thyroid hormones, which help regulate metabolism, growth and function of key organs. Vegans may not get enough iodine and be at risk of deficiency and possibly a goiter. In addition, foods such as soybeans, cruciferous vegetables and sweet potatoes may promote a goiter. However, just 1/4 teaspoon of iodized salt provides a significant amount of iodine.
  • Iron is a crucial component of red blood cells. Dried beans and peas, lentils, enriched cereals, whole-grain products, dark leafy green vegetables and dried fruit are good sources of iron. Because iron isn't as easily absorbed from plant sources, the recommended intake of iron for vegetarians is almost double that recommended for non-vegetarians. To help your body absorb iron, eat foods rich in vitamin C, such as strawberries, citrus fruits, tomatoes, cabbage and broccoli, at the same time as you're eating iron-containing foods.
  • Omega-3 fatty acids are important for heart health. Diets that do not include fish and eggs are generally low in active forms of omega-3 fatty acids. Canola oil, soy oil, walnuts, ground flaxseed and soybeans are good sources of essential fatty acids. However, because conversion of plant-based omega-3 to the types used by humans is inefficient, you may want to consider fortified products or supplements, or both.
  • Protein helps maintain healthy skin, bones, muscles and organs. Eggs and dairy products are good sources, and you don't need to eat large amounts to meet your protein needs. You can also get sufficient protein from plant-based foods if you eat a variety of them throughout the day. Plant sources include soy products and meat substitutes, legumes, lentils, nuts, seeds and whole grains.
  • Vitamins B-12 is necessary to produce red blood cells and prevent anemia. This vitamin is found almost exclusively in animal products, so it can be difficult to get enough B-12 on a vegan diet. Vitamin B-12 deficiency may go undetected in people who eat a vegan diet. This is because the vegan diet is rich in a vitamin called folate, which may mask deficiency in vitamin B-12 until severe problems occur. For this reason, it's important for vegans to consider vitamin supplements, vitamin-enriched cereals and fortified soy products.
  • Vitamin D plays an important role in bone health. Vitamin D is added to cow's milk, some brands of soy and rice milk, and some cereals and margarines. Be sure to check food labels. If you don't eat enough fortified foods and have limited sun exposure, you may need a vitamin D supplement (one derived from plants).
  • Zinc is an essential component of many enzymes and plays a role in cell division and in formation of proteins. Like iron, zinc is not as easily absorbed from plant sources as it is from animal products. Cheese is a good option if you eat dairy products. Plant sources of zinc include whole grains, soy products, legumes, nuts and wheat germ.

Ready, Start. Go!
I'm at the end of day one of my vegan diet month. I avoided the usual cookies that Fran brings to our senior bridge foursome every Monday and so far, so good.


Alex Wilber said...

Hi John,

I wanted to email you but couldn't work out how, so I thought I would just leave a comment here.

I just stumbled across your blog and have been reading with great interest. Over the last few months I have become very interested in health and nutrition; since my friend's mother has Parkinson's, I have been reading all over the internet on both topics. You are doing a great job with this blog, and your story is inspiring.

I wondered if you had come across "Paleo"-type diets? After all my reading I have become rather convinced by the arguments in favor of such a diet and I am going to give it a go.

The argument is essentially that for most of our evolutionary history we were hunter gatherers, and so we are probably very well evolved to cope with a hunter-gatherer diet, which means lots of vegetables, fruits, nuts, meat and fish. We may or may not be well adapted to eat foods which have become more recently available, such as grains, dairy or seed oils. The suggestion is that by sticking mainly to hunter-gatherer foods we can eat far more nourishing food, while avoiding foods to which we are poorly adapted (if you read about the lipid composition of seed oils, for example, you will quickly want to avoid ever using them again!).

If you are interested I very highly recommend either:
The Primal Blueprint by Mark Sisson; or
The Paleo Solution by Robb Wolf

Mark Sisson has an excellent blog which is well worth a few minutes of your time: .

If you are interested in more nitty gritty scientific detail, I also recommend The Perfect Health Diet by Paul Jaminet and Shou-Ching Jaminet (they are smart people despite the ridiculous name of their book). Their blog is worth reading, at

I don't have any vested interest in this, but I'm excited to have come across a set of dietary information which appears to make sense and be self-consistent. There's a shocking amount of poor research and misinformation on the subject of nutrition and sometimes researching it can be very hard going!

Best wishes,

Dr. Alex Wilber
(Physicist, Cambridge, UK)

John said...

Thanks. You make a good case for paleo/primal. Given my addiction to trying new things, that may be next if I get tired of or discouraged with vegan, I'm predisposed to believing that the answer to many of our health problems is not more prescribed meds and supplements but rather more attention to good, natural nutrition.

Jan said...


can I ask what were your experiences with the vegan and/or paleo diet?


John Schappi said...

I'm basically a do-it-yourselfer when it comes to diet and exercise. I pay attention to the recommendations from sources I trust but then do my own thing. I used to try following rigid rules for diet and/or exercise set forth by others but it never worked for me. I basically follow a Mediterranean/vegetarian diet of my own making