parikh 1 nishi parikh lifespan nutrition dr. michael zemel march

8/14/2019 Parikh 1 Nishi Parikh Lifespan Nutrition Dr. Michael Zemel March

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Parikh 1

Nishi Parikh

Lifespan Nutrition

Dr. Michael Zemel

March 5, 2009

Cardiovascular Disease Prevention by a Vegetarian Diet

According to the World Health Organization (WHO) and the US Centers for

Disease Control and Prevention (CDC), 16.7 million deaths were reported around the

globe due to different types of cardiovascular diseases (CVD). Many studies have

shown that diet plays a major role in the development or prevention of cardiovascular

diseases (1). One of the health properties of foods is their chemical composition. All

foods are not created equal. While some have high concentrations of saturated fatty acids,

others might have high concentrations of unsaturated fatty acids. For example, although

many foods contain fatty acids, the type of fatty acids makes a difference in how they

will be metabolized. Saturated fat has been linked to enhanced platelet aggregation

whereas, unsaturated fat has been linked with decreased platelet aggregation. Platelet

aggregation is a factor for atherosclerosis, leading to cardiovascular disease (2). As we

see, the foods that one consumes have a direct link with the nutrients consumed and also

the overall health of the consumer. Two major classifications of diets, vegetarian diet and

omnivorous diet, have a significant difference in the foods and nutrients consumed.

Foods involved in vegetarian diets have many healthy properties. Specifically, vegetarian

diets prevent cardiovascular disease.

A vegetarian diet mainly consists of consumption of fruits, vegetables, whole

grains, and legumes and nuts (3). Three main types of vegetarian diets play a role in


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collagen synthesis. It also affects endothelial cell function and adversely affects the

anticoagulant sytem, which may in part explain its atherogenicity. Also, high-sensitivity

C-reactive protein (hs-CRP) stimulates inflammation. This is important because

atherosclerosis can be advanced by inflammation in the artery along with the

accumulation and oxidation of cholesterol and LDL-C. Hence, controlled levels of hs-

CRP are encouraged to avoid cardiovascular risk (3).

Fruits, vegetables, whole grains, legumes and nuts contain numerous chemicals,

including antioxidants, that are involved in the prevention of cardiovascular disease.

Vegetarian diets contain cardioprotective compounds: fiber, antioxidants (Vitamin A,

Vitamin E, and Vitamin C), and phytochemicals of which non-vegetarian diets generally

lack. Plant-based diets also contain the cardioprotective minerals selenium and folate (1).

Some other beneficial nutrients and non-nutrients consumed by vegetarians include

polyunsaturated fatty acids, especially long-chain polyunsaturated fatty acids, such as

eicosapentaenoic acid, docosahexaenoic acid, monounsaturated fatty acids, milk and

phytochemicals, such as allicin( in garlic), polyphenols (in cocoa), isoflavones (in soy)

and anthocyanins ( in red wines and grape juice) . All of these nutrients and non-

nutrients have cardioprotective properties (3).

These compounds and some others are all involved with the prevention of

cardiovascular disease. Phytochemicals often have an antioxidant affect. Another set of

compounds, polyphenols, prevent agains LDL cholesterol oxidation and improve

endothelial dysfunction, whereas soluble and insoluble fiber and sterols help reduce

serum cholesterol levels. Also, antioxidants reduce oxidative stress and improve

endothelial function, folate protects against coronary heart disease by its ability to reduce


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homocysteine levels; some spices, herbs and condiments used in food preparations inhibit

platelet aggregation and prevent thrombosis. Additionally, garlic has

hypocholesterolemic, hypolipidemic, antihypertensive, antithrombotic,

antihyperhomocysteinemic properties, and an ability to inhibit platelet aggregation. All of

these properties are cardioprotective (1).

Also, according to Venket Rao and Amir Al-Weshahy, fruits and vegetables have

low levels of sodium. Consumption of fruits and vegetables displaces the consumption of

salty foods. A controlled consumption of sodium controls blood pressure, reducing

coronary heart disease risk (1).

Cereal, another significant component of vegetarian diets, has many heart

benefits. It contains fiber, linoleic acid, vitamin E, folate, and selenium. It also contains

phytochemicals such as phytoestrogens of the lignan family and several phenolic acids

with antioxidant properties. Legumes, vegetarian protein foods, contain fiber,

phytoestrogens, isoflavones and folate, all of which are cardioprotective properties of

legumes. Additionally, nuts contain much of the healthy fats omega-3 fatty acid alpha-

linoleic acid (1).

Some polyphenols are known to prevent some oxidative damage and endothelial

dysfunction. Red wine contains a type of polyphenol called resveratrol, green tea contains

catechins, and pomegranate juice contains catechins and quercetin. Grape seeds contain

proanthocyanidins . And tomatoes have been sufficiently studied and an inverse

relationship shows the incidence of coronary heart disease and the consumption of

lycopene, a carotenoid antioxidant phytochemical (1). As a reminder, all of these plant

compounds control serum cholesterol, blood pressure, oxidative stress, homocysteine


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levels and improve endothelial dysfunction. All of these factors decrease risk of

cardiovascular disease (1).

Several studies have shown occurrences of favorable low density lipoprotein

cholesterol levels, total cholesterol levels, antioxidant levels, blood pressure levels, and

high-sensitivity C-reactive protein (hs-CRP) levels in vegetarians compared to

omnivores. While low-density lipoprotein, total cholesterol, and antioxidant levels are

associated with accumulation and oxidation of cholesterol and LDL-C, hs-CRP levels

affect inflammation status. Exclusively, hs-CRP is considered a single independent

cardiovascular risk factors (3).

A study found in European Journal of Clinical Nutrition measured the fasting

blood levels for glucose, cholesterol, triglyceride, high-density lipoprotein cholesterol,

low-density lipoprotein, white blood cell count, high-sensitivity C-reactive protein, and

homocysteine in Taiwanese vegetarians compared to omnivores. The vegetarians had to

have been on an ovo-lactovegetarian diet for at least one year to be studied as

vegetarians. The study shows no significant differences in age, body mass index, blood

glucose, white blood cell count, triglyceride and HDL-C levels in the vegetarians and

omnivores studied. However, there were statistically significant differences in gender

ratio, smoking rate, body weight, body height, total cholesterol, LDL-C and uric acid.

Also, vegetarians had significantly lower levels of hs-CRP and higher levels of

homocysteine compared to omnivores. This study and others have shown that vegetarians

have a better lipid profile and a better controlled blood pressure (3).

Although homocysteine levels are high in vegetarians, the cause is vitamin B12

deficiency caused by the exclusion of vitamin B12 foods. Furthermore, no significant


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difference in carotid atherosclerosis, as measured by ultrasound, was found between these

two groups. This implies that even with the higher homocysteine levels found in

vegetarians, the carotid artery intima-media thickness and extra cranial carotid artery

plaque score of vegetarians were, at least, not worse than in omnivores. Additionally, it

appears that homocysteine is only one of the risk factors predisposing to atherosclerosis,

whereas, the hs-CRP level represents the overall vascular inflammation status, which

implies the presence of vascular damage, and is thus a direct sign of cardiovascular

disease. (3) Therefore, a vegetarian diets effect on maintaining low hs-CRP levels is

much more significant than its possible occurrence of high homocysteine levels (3).

Another study, studied the effects of long-term vegetarian diets on cardiovascular

autonomic functions in healthy postmenopausal women. This study discovered that

women who had been vegetarians for at least two years had more optimal blood pressure

and favorable lipid concentrations compared with omnivores, and that vegetarian diets

may facilitate vagal regulation of the heart and increase baroreflex sensitivity(8)

Finally, a case-control study suggests the benefits of foods directly with the risk

of myocardial infarction. Norwegian men and postmenopausal women were studied.

Subjects had to have no history of myocardial infarction or other serious illness. Upon a

myocardial infarction occurrence in a study subject, dietary intake was analyzed for the

previous year using a FFQ, Food Frequency Questionairre. Food consumption was

compared between the cases and the controls. Study mediators created an a priori diet

score by having a high score for diets that are hypthosized as healthy diets. These

included low meat intake and high whole grain, vegetable, fruit, nut and legume intake.

The foods in the healthy ranking were considered as protective against and those in the


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low rankings were considered as possibly causative of myocardial infarction. Some of the

foods that were considered protective included cheese and yogur, low fat dairy, tea, wie

beer, liquor, wholegrain breads, wholegrain breakfast cereals, fish, chicken, non-

hydrogenated vegetable oil, dressings, mayonnaise, and sauces, cruciferous vegetables,

tomatoes, salad, other vegetables, nuts, and soup. Eight foods were considered as

contributing to myocardial infarction risk: liver, high-energy drinks, red and processed

meats, chips and snacks, sweets, and pizza. Results of the study concludes certain foods

as particularly protective: tomatoes, salad, whole-grain breakfast cereal, cruciferous

vegetables. Butter and margarine were associated with risk of myocardial infarction.

However, high-fat dairy intake was greater in controls. More importantly, a strong and

inverse association was observed between the a priori healthy diet pattern score and risk

of myocardial infarction. The strength of the association between the healthy diet pattern

score and risk of myocardial infarction underscores the important role of diet in the

disease. (9) This study provides further evidence of the inverse relationship of fruits,

vegetables, and whole grains and heart disease. Also, a diet high in vegetarian foods and

low in meat products is cardioprotective. Such results have been seen in other studies

with other populations as well (9).

As we now see, vegetarian diets are not only for the particularly religious. A

vegetarian diet can contribute to numerous health benefits, specifically heart health, and

the prevention of cardiovascular diseases. Not only do vegetarian foods have many

compounds (i.e., fiber, sterols, antioxidants, folate, phytochemicals, linoleic acid, omega-

3 fatty acid alpha linoleic acid, vitamin E, selenium, and isoflavones) that prevent many

risk factors for cardiovascular diseases: abnormal blood lipids, systemic hypertension,


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high homocysteine levels, and abnormal blood coagulation, vegetarian foods are limited

in the compounds that contribute to these risk factors as well (3,1). By limiting LDL-C

levels and its oxidation, increasing hs-CRP levels, and controlling blood pressure, a

vegetarian diet is considered as a cardioprotective diet (3).

References

1. Rao V, Al-Weshahy A. Plant-based diets and control of lipids and coronary heart

disease risk. Curr AtherosclerRep. 2008; 10: 478-85.2. Fraser GE. Diet and coronary heart disease: beyond dietary fats and low-density-

lipoprotein cholesterol.Am J Clin Nutr. 1994; 59: 1117S-23S.

3. Chen CW, Lin YL, Lin TK, Lin CT, Chen BC, Lin CL. Total cardiovascular risk

profile of Taiwanese vegetarians.Eur J Clin Nutr. 2008; 62: 138-144.4. Brown J. Adolescent nutrition. Nutrition through the lifecycle. 2008; 3:360.

5. Encyclopdia Britannica Inc.. Cardiovascular disease.

Accessed March 5, 2009.

6. Encyclopdia Britannica Inc.. Atherosclerosis.

Accessed March 5,2009.

7. Roberts WC. The cause of atherosclerosis.Nutr Clin Pract. 2008; 23: 464-467.

8. Chin-Hua Fu, Yang CCH, Chin-Lon L, Kuo TBJ. Effects of long-term vegetarian dietson cardiovascular autonomic functions in healthy postmenopausal women.Am J Cardiol.

2006; 97: 380-3.

9. Lockheart MSK, Steffen LM, Rebnord HM, Fimreite RL, Ringstad J, Thelle DS,Pederson JI, Jacobs DR. Dietary patterns, food groups and myocardial infarction : a case-

control study. Br J Nutr. 2007: 98: 380-387.

parikh 1 nishi parikh lifespan nutrition dr. michael zemel march

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