in heart disease prevention
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.
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
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.
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.
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 non-fat
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 fibre in your diet.
Fibre is found in soluble and insoluble forms. Soluble fibre decreases
cholesterol in the serum by trapping the cholesterol-bile acid in the gut.
The trapped cholesterol is then excreted in the stool. Insoluble fibre
helps with digestion, lowers rates of colon cancer and can improve
numerous bowel related problems.
The current recommendation for daily fibre 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 fibre per day, you decrease your risk of heart
attack by 55 percent as compared to someone taking in 12 grams of fibre
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 fibre 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 fibre 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 fibre 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 fibre.
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.
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.
7. Consider supplementation with anti-oxidants.
Antioxidants decrease the risk of vascular plaque formation and narrowing
caused by LDL cholesterol by decreasing itís 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
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.
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, itís 10-20 mcg/day and for vitamin B-6, itís
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.
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 flavouring 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 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.