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Diets

Vegetarian, vegan, low-fat, mediterranean and paleolithic

 

For a great review of several popular diets and their relationship to patterns in cardiovascular disease, please see the article in Circulation from 2006:

“Impact of Dietary Patterns and Interventions on Cardiovascular Health”

 

Vegetarian:

Does not eat meat of any kind, but generally eats other animal products (such as dairy, eggs, etc).


Vegetarians generally have a lower incidence of coronary heart disease (as less obesity, lower blood pressure and lower serum cholesterol are trends) and some cancers (prostate and colon).

According to one study, vegetarians have a 24% reduction in mortality due to heart disease and a 40% reduction in cancer mortality compared with meat-eaters.¹  (Link to Article)

Nut consumption, which is prevalent in many plant-based, Meditteranean and Asian diets, appears to be protective against ischemic heart disease.² (Link to Article)

There are no major nutritional concerns in a well-planned vegetarian diet

For more information, a good book is: The Dietitian’s Guide to Vegetarian Diets: Issues & Applications. Second Ed 2004. By Reed Mangels, Mark Messina and Virginia Kisch Messina.

 

Articles related to Vegetarian diet:

The effect of vegetarian diet, plant foods, and phytochemicals on hemostasis and thrombosis. Am J Clin Nutr. 2003 Sep;78(3 Suppl):552S-558S.

 

Vegan

Does not eat meat or animal products of any kind.

Benefits:

  1. May align with patient’s moral or environmental goals.
  2. Average cholesterol of vegans is even less than vegetarians (133 vs 156)³. Studies show that for every 1% drop in cholesterol, there is an associated 3-4% drop in heart disease (Link to Article).

Drawbacks:

Vegans should be supplemented with Vitamin B12 (as this nutrient comes mainly from animal products such as meat and eggs), and they may tend to be low in Calcium, riboflavin and zinc.

Also, as plant protein is estimated to be only about 85% digestible, vegans should consciously increase their intake of daily protein.

 

Low Fat

One example is the Ornish diet:  based on whole grains (rice, wheat, corn), legumes, fruit and vegetables, low to moderate amts of white meat, fish, egg white, non-fat dairy foods, and no red meat, oil/fat, sweets or nuts.


About 12-20% of calories in the Ornish diet are from fat; it is low in all fatty acids and cholesterol, high in carbohydrate (60-70% of calories), and adequate in protein.

Ornish diet PLUS meditation, exercise and stress reduction actually has been shown to reverse coronary atherosclerosis.

 

Drawbacks:

Cuts back on healthy fats, such as omega 3s, which have proven health benefits.

Decreasing fat intake may increase overall food intake, as fat is satiating and increases not only the pleasure of eating but also the sensation of fullness.

Low-fat diets can lead to lower HDL and higher triglycerides (especially if patient is sedentary, replaces fat calories with carbohydrate calories, and does not experience weight loss with the diet).

Current recommendations regarding lowering dietary fat*:

1. Eliminate all trans fat  (look at ingredient label, and avoid foods with “hydrogenated oil” or “partially hydrogenated oil”. Some packaged foods will advertise “0 trans fats” but may still have up to 0.5g per serving. Looking at the label is the only way to know for sure). 

2. Consume healthier fat types such as monounsaturated (olive oil, canola oil, nuts and seeds) and omega-three fatty acids (walnuts, fatty fish, flax seed/oil) instead of saturated fat.

*Reference: Practical Applications of Fish Oil (Omega 3 Fatty Acids) in Primary Care, Robert Oh, MD, J Am Board Fam Pract. 2005; 18 (1): 28-36.

 

Mediterranean Diet

The diet is based on grains (e.g. bread and pasta), legumes, vegetables, fruit, nuts/seeds, olive oil as the main fat source, wine, and moderate amounts of fish, white meat, dairy and eggs. Red meat is eaten sparingly.


Those living in Greece, southern Italy and southern France have lower incidences of cardiovascular disease and some cancers than in the US.

Approx 40% of calories comes from fat (as compared to the FDA recommendation of 30%), the content of which is low in saturated fat and high in monounsaturated fatty acids and cholesterol. About 40-50% of calories are from carbohydrate, and 10-20% from protein.

Advantages:

The Lyon Heart Study (a randomized control clinical trial with n=605) showed evidence that the Mediterranean Diet reduces the incidence of recurrent cardiovascular events in patients with heart disease.
                For more on the Lyon Heart Study and other pertinent articles:
                http://www.americanheart.org/presenter.jhtml?identifier=4655
                http://circ.ahajournals.org/cgi/content/full/99/6/779
                http://circ.ahajournals.org/cgi/content/full/103/13/1823

 

“Analyses of the dietary pattern of the Greek Isle of Crete show a number of protective substances, such as selenium, glutathione, a balanced ratio of omega-6 to omega-3 essential fatty acids, high amounts of fiber, antioxidants (especially resveratrol from wine and polyphenols from olive oil), and vitamins E and C, some of which have been shown to be associated with lower risk of cancer, including cancer of the breast.”¹

Epidemiologic research at the Harvard School of Public Health supports the Mediterranean diet for the prevention of cardiovascular disease in US populations. See www.hsph.harvard.edu/nutritionsource/pyramids.html

 

 

Paleolithic Diets

(see pertinent articles below)

Based upon a hunter-gatherer/forager lifestyle, and thought to be evolutionarily compatible with our physiology and nutritional needs.The “Zone” diet was loosely based on the Paleolithic diet.


First introduced by S. Boyd Eaton, MD, in The Paleolithic Prescription*.

He proposed that people are genetically programmed to consume a diet based on neopaleiolithic patterns of nutrition, arguing that the human genome has changed little in the past 40,000 years.³ Ethnographic studies show that humans have evolved with a diet that was 35% plant based and 65% animal based. However, because the available meat in ancient times was wild game, it was relatively lean with less saturated fat and a favorable omega 3: omega 6 ratio in the range of 1:1 to 1:3.

High in animal foods (wild game and fish), fruits, roots, legumes, nuts, without added oil, sugar or dairy.

30% of calories from fat (varying between 28-58%), but low in saturated fat and high in cholesterol

About 40% or fewer calories from carbohydrates, and high (about 40% of kcals) in protein.

There are no long-term clinical trials to support or negate whether the diet truly produces positive health outcomes. 

 

Articles related to Paleolithic diets:

The paradoxical nature of hunter-gatherer diets:  meat-based, yet non-atherogenic. European Journal of Clinical Nutrition (2002) 56, Suppl 1, 42–52

 

Cardiovascular Disease Resulting From a Diet and Lifestyle at Odds With Our Paleolithic Genome: How to Become a 21st-Century Hunter-Gatherer. Mayo Clinic Proceedings, Jan 2004 Vol 79, No 1, 101-108.

 

Plant-animal subsistence ratios and macronutrient energy estimations in worldwide hunter-gatherer diets. American Journal of Clinical Nutrition, Vol. 71, No. 3, 682-692, March 2000

* SB Eaton, et al. Paleolithic nutrition revisited: A twelve-year retrospective on its nature and implications. European Journal of Clinical Nutrition, 1997, 51: 207-206.

 

 

General pertinent articles

 

Impact of Dietary Patterns and Interventions on Cardiovascular Health. Circulation. 2006;114:961-973

 

Dietary Prevention in Sudden Cardiac Death. European Heart Journal (2002) 23, 277–285

 

Comparison of the Atkins, Ornish, Weight Watchers, and Zone Diets for Weight loss and Heart disease risk reduction: a randomized trial. JAMA. 2005; 293(1):43-53

Clinical Events in Prostate Cancer Lifestyle Trial: Results From Two Years of Follow-Up. Urology, Vol  72, Issue 6, Pages 1319-1323 (December 2008)

 

 

 

Works cited

  1. Key TJ, et al: Mortality in vegetarians and non-vegetarians: Detailed findings from a collaborative analysis of 5 prospective studies. Am J Clin Nutr 70:516S-524S, 1999.
  2.  Sabate J: Nut consumption, vegetarian diets, ischemic heart disease and all-cause mortality; Evidence from epidemiologic studies. Am J Clin Nutrition 70:500S-503S, 1999
  3. Kohatsu, Wendy, MD. Complementary and Alternative Medicine Secrets. Hanley & Belfus, 2002: 125-136