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Nutrition in Heart Disease Prevention
 
Open/Close text Introduction

One quarter of the U.S. population or 70 million people have cardiovascular disease. The good news is that new medical technologies and patient education have allowed a 26.5% decrease in cardiovascular disease deaths in the US from 1992 to 2002.  Despite that, each year in the United States, almost 500,000 die from heart attacks which remain the single leading cause of mortality. 

Cardiovascular disease significantly influences the pilot group. The Aeromedical Office of the Air Line Pilots Association (ALPA) reports that in 1997, cardiovascular cases represented twenty five percent of their total case load.  ALPA data shows that approximately one third of pilots who lose their medical licenses do so because of cardiovascular diseases. For additional information on heart disease in pilots, please see the VFS articles on Coronary Artery Disease and Cholesterol Reduction in our Information Resource section.

The major risk factors for cardiovascular disease include high blood pressure, increased cholesterol, low HDL (less than or equal to 35 mg/dl), diabetes, smoking, obesity, increasing age,  sedentary lifestyle and family history.  Of these risk factors, smoking cessation, sedentary lifestyle and dietary modification may be managed by any individual without necessarily consulting a physician.   Physicians can provide valuable information, analysis and intervention for those who desire.  Dietary modification directly affects obesity, diabetes and cholesterol.

Open/Close text Cholesterol Risk Factors

Serum cholesterol values exceeding 200 mg/dl, LDL (low density lipoproteins) greater than 130 mg/dl, and triglycerides greater than 200 are considered elevated. An HDL (high density lipoprotein) less than 35 is also associated with an increased cardiovascular risk. Genetics factors explain between 20 and 50 percent of the cholesterol elevation in the general population while diet, weight, and exercise level account for the rest of the cholesterol variation.

The higher percentage of saturated fat in your diet, the higher your total cholesterol will be. The higher your total cholesterol, the higher your death rate from cardiovascular disease will be. The following table shows this relationship.

Country % sat fat in diet Avg. Chol. CV death rate /100,000
China 7% 158 99
US 13% 216 373
Finland 20% 241 730

Obesity raises the LDL levels and lowers the HDL cholesterol. Exercise increases the HDL cholesterol.  Smoking lowers HDL.

Open/Close text Goals

The goals for lowering your cholesterol depend on the number of other risk factors you have, the LDL level, and whether you already have cardiovascular disease. In general without pre-existing cardiovascular disease, your ideal LDL would be less than 130 mg/dl. With cardiovascular disease, your LDL should be less than or equal to 100.  With an LDL of 100 or less, there is a significant decrease in risk of plaque formation.  The ratio of total cholesterol to HDL should be as low as possible, ideally less than 4.5.  See the American Family Physician Patient Information: "Goals for Lowering Your Cholesterol"

Currently, no FAA standards for cholesterol exist.  The FAA has demonstrated concern about cholesterol as a cardiovascular risks factor as evidenced by the 1996 NPRM proposing mandatory cholesterol testing in airman medical examinations. This proposal was withdrawn after strident objections from many sources and pilot advocate groups.

Open/Close text What can be done for an elevated cholesterol ?

1.  Decrease fat intake, especially saturated fat and trans fatty acids.

Three major sources of saturated fats in the diet are fatty meats, butter and margarine and dairy products made from whole or 2% milk.   Eliminating these will reduce saturated fat consumption by half.

Limit red meats including beef, pork and lamb to 20 ounces per week.  When eating meat, select the leanest cuts and remove all visible fat before eating.  Use poultry, fish, and legumes to replace red meat several times a week.  Avoid luncheon meats, frankfurters, and sausage.  Skim fat off broths, soups, and gravies.  Bake, broil or boil meats.  Switch to nonfat or 1% milk.   Use cheeses made with part skim milk.  Decrease your intake of rich dishes made with butter, cream, palm oil, coconut oil, and cocoa butter.  Avoid food products bearing the terms hardened or hydrogenated vegetable oil.  Use only small portions of fresh butter, margarine and mayonnaise as spreads. Use salad dressings sparingly.

2.  Increase the consumption of omega-3 fatty acids  (n-3 fatty acids) and monounsaturated fats.

Recent studies in the United States have shown that two to three servings of fish (which is a good source of omega-3 fatty acids) may reduce mortality by about 30% among patients who have survived their first heart attack. The omega-3 fatty acids have this effect by lowering the cholesterol and triglyceride levels and inhibiting platelets from forming clots in the blood.

Mediterranean diets have nearly the same percentage of total fat as American diets, but it is nearly all monounsaturated fats and omega-3 fatty acids.  People who followed the Mediterranean diet after heart attacks had a 70% reduction in mortality over those on a standard American diet. Large doses of omega-3 fish oil supplements can be detrimental by increasing LDL, increasing blood sugars in diabetics, decreasing blood clotting and Vitamin A and D toxicity.

Flax oil is probably the richest source of omega-3 fatty acids.  Using 10-15 grams per day, about a tablespoon, should be adequate.  Both capsule and liquid forms are available.  Flax oils should be kept refrigerated in an opaque plastic container.  Heating or cooking flax oil breaks down the essential fatty acids.  You should look for flax oil that has been extracted at temperatures less than 104 degrees Fahrenheit.

Monounsaturated fats are found in canola oil, olive oil and monounsaturated safflower oil.  Corn oil and margarine's with vegetable oil spreads have polyunsaturated fats which are detrimental.  Highly saturated fats are found in peanut, palm and coconut oils and are often mixed in candies and chocolates.

Some nuts are also a good source of monounsaturated fats including macadamia, walnuts, almonds and pecans.  Peanuts have high polyunsaturated fats and should be avoided.

3.  Increase soluble fiber in your diet.

Fiber is found in soluble and insoluble forms. Soluble fiber decreases cholesterol in the serum by trapping the cholesterol-bile acid in the gut. The trapped cholesterol is then excreted in the stool.  Insoluble fiber helps with digestion, lowers rates of colon cancer and can improve numerous bowel related problems.

The current recommendation for daily fiber is 25 to 35 grams per day. The average American diet consists of 8-12 grams per day.

If you take in 30 grams of fiber per day, you decrease your risk of heart attack by 55 percent as compared to someone taking in 12 grams of fiber per day. In addition, for every additional 10 grams added to your diet, you decrease your heart attack risk by twenty per cent. Oatmeal is an excellent source of fiber that has been shown to lower cholesterol with daily intake. Other sources include whole grains, fruits and vegetables and beans.  To get 30 grams of fiber per day, one would need to eat 2.9 cups of pinto beans, 11.2 quarts of popcorn, 5.6 cups of raisin bran, 34 raw apricots, 25 whole grapefruit, 6.3 cups of broccoli, or 10 baked potatoes. Given our fast paced lifestyles, dietary supplementation is usually necessary to achieve this level of fiber intake.

4.  Increase soy products and legumes.

Both soy products and legumes lower LDL cholesterol without affecting HDL levels.   Tofu is a soy product that can be used in many recipes.  Some restaurants are offering soy substitutes for meat dishes. Soy products are rich in non-fat proteins.

Soy contains "phytoestrogens", or plant based estrogens, which may be the mechanism of action for protecting against heart disease.  Women have a much lower incidence of heart disease than men until they pass menopause when estrogen levels fall off.

Legumes include all forms of beans and bean products.  In addition to being an excellent source of non-fat protein, they are very high in both soluble and insoluble fiber.

5.  Limit your the daily intake of cholesterol to < 300mg/day.

The foods that are rich in cholesterol are egg yolks, butter, cream, cheese, dairy product with 2% or more milk fat, sweetbreads, liver, and other organ meats, and shellfish.

Most foods now contain levels of cholesterol contained in each serving size.  As long as your serving size is the same as the one listed on the container, you can track your daily input of cholesterol.  Be aware that some food labels may indicate the product is fat-free, but this does not mean it is cholesterol free.

For those individuals with risk factors for cardiovascular disease or pre-existing heart disease and elevated cholesterol levels, restricting cholesterol intake to less than 200 mg per day is desirable.

See the VFS artcle on Cholesterol Reduction for more info.

6.  Exercise 30 minutes per day most days of the week.

This will lead to weight reduction and improved sugar control and thereby, increased HDL levels. It is less important what type of exercise you do and more important that you exercise consistently.  Aerobic type activity with heart rates sustained at 65-80% of your predicted maximum heart rate is the most beneficial for cardiovascular health.  The predicted maximum heart rate is calculated by subtracting your age from 220. 

Dr. Kenneth Cooper, the "father of aerobic exercise", now cautions people not to overexert themselves when exercising.   This may increase "free radical formation" and overwhelm the antioxidants available to protect against cholesterol deposition in the arteries.

See the VFS article on Fitness Assessments & Exercise Recommendations for more info.

7.  Consider supplementation with anti-oxidants.

Antioxidants decrease the risk of vascular plaque formation and narrowing caused by LDL cholesterol by decreasing it?s oxidation. It is the oxidized LDL that gets deposited in the vessel wall causing plaque formation.

High intakes of vitamins E (no greater than 800 units/day)  are needed to substantially decrease plaque formation.  There is preliminary information to support vitamin E's positive effect in reducing the risk of coronary artery disease at doses of 400-800 mg per day.  People on blood thinning medications (anticoagulants) or with bleeding problems should not start taking vitamin E without consulting their physicians.  The natural d- form of vitamin E is more active than the synthetic dl- form.

Evidence that vitamin C and vitamin A/beta carotene can reduce heart disease is mixed.  One epidemiological study actually showed an increased risk of death on people using vitamins A and C.  Other studies have shown a protective effect.  Maximum amounts of vitamin A  should be 5,000-10,000 mg while beta carotene does not have a known toxic level.   Recommendations on vitamin C intake vary from 500 mg to over 20 times that amount.

Selenium is another anti-oxidant. Dr. Kenneth Cooper suggests using selenium with vitamin E, vitamin C and beta-carotene to reduce the risk of heart disease.

These vitamins can be obtained from fruits and vegetables, although some diets may be inadequate and supplementation may be desirable.   A June 2002 article in The Lancet, a reknowned British medical journal, published original research on the positive effects of a diet rich in fruit and vegetables on reducing heart disease, primarily because of the antioxidant effects.  Additional information from the Gatorade Sports Institute documents the cardioprotective effects of antioxidants.

See the VFS article on Vitamins and Minerals for more info.

8.  Increase intake of Vitamins B-12, B-6, and folate.

These substances are important in the breakdown of an amino acid called homocysteine. Homocysteine is now considered to be a vascular toxin that results in blockage of arteries, heart attacks and strokes. It is thought to be responsible for 5% to 10% of the risk of heart disease. Vitamin B-12 is found in animal protein foods.   Vitamin B-6 is found in meats, whole grains, fish, poultry, soybeans, bananas, prunes, cauliflower, cabbage, and avocado.  Folate is found in orange juice, green leafy vegetables, and fortified cereals. The current Recommended Daily Allowances are probably too low. The amount of folate you should take as a supplement is 1-2 mg/day. For vitamin B-12, it?s 10-20 mcg/day and for vitamin B-6, it?s 10-15 mg/day.

The Institute of Medicine has updated Dietary Reference Intakes (DRI) which are more specific than the currently used Recommended Daily Allowances (RDA) found on vitamin bottles. 

9.  Don't use tobacco in any form.

Smoking is the largest single risk factor for heart disease, stroke, lung cancer and oral cancers.  It is associated with many other diseases and premature aging.  Smoking lowers HDL cholesterol levels and increases the risk of clotting of the blood.

See the VFS article on Smoking Cessation & Tobacco Abuse for a full discussion.

10.  Take one aspirin per day

Several studies have demonstrated a reduced risk of heart attacks in men who use aspirin daily.  The optimum dose is not established. Recommendations vary from 81 mg (one baby aspirin) to 500mg (one "extra strength" aspirin).  There is a slight increased risk of a bleeding type stroke in aspirin users.  Data for women using aspirin are not clear.  Individuals with stomach ulcers or using steroids should use coated aspirin preparations or avoid aspirin.

11.  Reduce sodium intake to lower blood pressure

Salt, in the form of sodium chloride, can significantly raise blood pressure in some people.  Elevated blood pressure is also a significant risk factor for heart disease and stroke.  Sodium intake should be under 2,500 mg per day (one teaspoon).  Look for high salt content in foods that come in cans or are wrapped in plastic.  Low salt foods include fresh fruits, vegetables and meats.

For those who need the flavoring of salt, some commercial "salt substitutes", which contain magnesium or potassium instead of sodium, can be healthy alternatives.  Potassium in the diet increases sodium loss from the kidneys.  Magnesium may play a role in heart and muscle function and may be depleted in illness.

12.  Control weight through calorie restriction

Maintaining an ideal body weight or body mass index is very helpful in controlling blood pressure and reducing the risk of diabetes, a significant risk factor for heart disease, stroke and blindness.  a full discussion of strategies for body shaping and weight control is found in the VFS article on Obesity and Weight Control.

13.  See your physician about cholesterol lowering medications

Some people, despite good efforts at lowering cholesterol using the above techniques, are unable to reach their goals.  The reasons for inability to reach these goals are numerous, but commonly, the person's genetic background is a major determinant.  Individuals do not have any control of their genetically determined ability to effect changes in cholesterol and triglyceride levels. After adequate trials of diet, nutrition and lifestyle modifications, those people who have not reached their goals should consult with their physician about medications to lower cholesterol.  The medications are very effective and are allowed by the FAA.   See the VFS article on Cholesterol Reduction and the American Family Physician article on Effective Use of Statins to Prevent Coronary Heart Disease.

Open/Close text VFS Aeromedical Assistance

For a more specific personal explanation to your questions or those concerning aeromedical certification, contact VFS for a private consultation though our Confidential Questionnaire.   If you are a VFS Corporate Member, these services are FREE to you
 
 
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