Dietary fats and cholesterol receive considerable attention from the medical community, food manufacturers and individuals concerned with their health. Research conclusively demonstrates that elevated cholesterol in the blood is a significant, and modifiable, risk factor for heart disease. Subtypes of cholesterol may be independent risk factors or protective for heart disease. The role of triglycerides is less well defined, but many feel they also contribute to heart disease. Obesity is also a known promoter of heart disease. Dietary fat contributes significant numbers of calories to Americans? daily diets, to obesity and to several forms of cancer.
American Heart Association Guidelines
The American Heart Association publishes specific guidelines for dietary recommendations for fat and cholesterol. The AHA also recommends dietary and medical interventions for people with elevated cholesterol. The public now can calculate approximate daily intake of calories, total and unsaturated fat, cholesterol and fiber as a result of recent FDA food labeling mandates. Despite the wealth of information available on the subject, many people are confused by the bold claims and confusing details regarding control of cholesterol.
FAA Policy on Cholesterol Screening
In the early 1990’s, the FAA considered measuring blood cholesterol in pilots in their Notice of Proposed Rulemaking changing FAR Part 67. Although no disqualification was recommended for elevated cholesterol levels, values above 300 mg% would have triggered a cardiovascular evaluation. Numerous objections from many interested parties were validated and the FAA dropped this proposal from the new FAR Part 67 adopted in September 1996. No blood testing is routinely required nor is any level of cholesterol disqualifying. However, nearly every cardiovascular condition requiring evaluation for the FAA includes a mandatory report of the pilot’s cholesterol, triglycerides and glucose levels.
Cholesterol Monitoring for Pilots
The control of blood lipid levels (cholesterol and triglycerides) is an important step in controlling heart disease, stroke and heart failure. Anyone interested in their long-term health and well-being should attempt to reduce their lipid levels if elevated. Pilots traditionally have had some reluctance to monitor lipid levels and intervene against elevated levels for fear of adverse effects on their medical certificate. This reluctance is unjustified. Many methods for lowering cholesterol exist without using medication. Cholesterol control with dietary changes and nutritional supplements is not reportable on the FAA Airman’s Medical Application.
The FAA currently approves most lipid lowering medications on the market in pilots who tolerate them well without side effects. FAA physicians look favorably on pilots who are taking active steps to control their cholesterol levels as part of any cardiovascular health program. How should pilots address this issue?
Most physicians recommend obtaining a blood sample to determine baseline cholesterol, triglycerides and possibly blood sugar levels. To provide a proper sample, one should fast (nothing to eat or drink except water) for 12-14 hours before the blood is drawn. Abstinence from alcohol for several days prior to the test may give lowered triglycerides levels. Dietary changes in the few days before testing have little effect on cholesterol levels. Monitoring cholesterol levels after instituting medication or dietary changes is not recommended at intervals less than several months. Ideally, each blood test for lipids should be done at the same laboratory to give greater consistency in comparing results.
Most reports of blood lipids are divided into several components. The total cholesterol is always reported. Levels below 200 mg% are desirable, lower in some medical conditions. The total cholesterol (TC) is divided into the high density lipoproteins (HDL), low density lipoproteins (LDL) and very low density lipoproteins (VLDL). Triglycerides (TG) are reported separately.
HDL is the “good cholesterol”. HDL may actually aid in reversing cholesterol deposits on the lining of the blood vessels. Higher levels seem to give some protection against heart disease while levels below 30 mg% are an independent risk factor for heart disease. Frequently a ratio of the TC to the HDL is reported. A TC/HDL ratio of less than 5.0 is desirable and less than 3.5 is optimum. As the ratio rises, so does the risk of heart disease.
LDL is the “bad cholesterol”. Levels under 130 mg% are acceptable while those above 160 mg% indicate the need for treatment. Many times, treatment is appropriate at significantly lower levels of LDL. For those people with known coronary artery disease, many physicians are recommending lowering LDL cholesterol levels below 100 mg% to possibly reverse cholesterol deposits in the arteries. VLDL is infrequently reported as the significance of this factor is not established.
Triglycerides (TGs) should also be under 200 mg%, but the significance of elevated levels is not fully explained. Other components of the lipid profile that are less frequently measured, but associated with heart disease, include Apoprotein B and lipoprotein (a).
Risk Factor Reduction
Many steps are available for the person with elevated cholesterol interested in reducing the risk of heart disease.
First, the individual should reduce daily cholesterol intake to less than 200 mg while fats should make up less than 30% of total calories. Many diet experts suggest a diet containing approximately 20% fats to lower the risk of several diseases. Diets rich in grains, fruits and vegetables are ideal. Avoiding unmodified dairy products, rich meats and saturated fats and oils found in many processed foods reduces fat and cholesterol. Low fat alternatives are available. Reading the nutritional labels on foods is enlightening and possibly surprising. Poly- and mono-unsaturated oils may actually lower cholesterol.
Publicity for the high protein, low carbohydrate diets (Atkins) in November 2002 at the American Heart Association Annual Scientific Meeting generated much confusion about a proper diet.
Exercise is an important step in lowering total cholesterol and raising HDL cholesterol.
Smoking cessation will also raise HDL. One to two ounces of alcohol (a 12 oz. beer, one glass of wine or a single mixed drink) daily may be helpful in improving cholesterol. More than this amount is harmful.
Soluble fiber and omega-3 fatty acids will improve cholesterol profiles. Good sources of omega-3 fatty acids include fatty fish products (salmon) and flax seed oil. Flax seed oil is an excellent source of essential fatty acids in the diet, including the very desirable omega-3 and omega-6 fatty acids.
Adequate dietary intake of certain vitamins including niacin, vitamin E, some B vitamins and folate may be protective.
Increasing fiber intake in the diet may also lower cholesterol. Research indicates that soluble fiber may interfere with the absorption of cholesterol in the intestine and significantly lower cholesterol and triglycerides levels. Fruits, grains and vegetables are high in fiber. The average American diet includes about 5-10 grams of fiber daily. The recommended amount is 25-35 grams.
Many people find it hard to increase their fiber intake to meet these recommendations with non-medicinal nutritional supplements. These supplements may be very effective in lowering cholesterol. They are not reportable to the FAA or your AME as a medicine. Consult with your personal physician or a preventive medicine specialist for details on available supplements.
Next, the person should avoid all tobacco products and participate in a program of regular aerobic exercise. Discuss an exercise program with your physician if you do not already engage in regular activity. These steps will lower the total cholesterol and raise the HDL. The TC/HDL ratio may drop significantly. Weight reduction will also help lower total cholesterol. See the AMAS articles on Smoking Cessation and Tobacco Abuse, Obesity and Weight Control. Nutritional supplements and vitamins may also play an important role in cholesterol reduction.
Cholesterol Lowering Medications
For those who continue to have elevated lipids despite non-pharmacological steps or those who have other risk factors for heart disease or marked elevated lipid levels, intervention with medications may be prudent. Several categories of medications are available. The selection should be determined after discussion with your physician about your lipid profile, co-existing medical conditions, family history, lifestyle and costs and side effects of the medications.
HMG Co-A Reductase Inhibitors – Statins
The HMG Co-A reductase inhibitors, also known as “statins”, are the most widely used class of medication to lower cholesterol. They work by blocking an enzyme that converts dietary fats into cholesterol in the liver. The statins are relatively recent entries into the market, but their popularity is due to their excellent tolerance and tremendous effectiveness. They have very few side effects and may be taken once daily in most cases. There is some potential to elevate liver enzymes so some physicians will add liver testing to repeat cholesterol testing. The major drawback, as with any new and successful drug, is their cost. Examples include pravastatin (Pravachol), lovastatin (Mevacor), simivistatin (Zocor), fluvastatin (Lescol), atorvastatin (Lipitor), and Crestor (rosuvastatin) and are just a few of those authorized by the FAA.
Niacin is a B vitamin that is effective in lowering LDL, TC, TG and TC/HDL ratio. It also significantly raises HDL. All of these effects are desirable. The major advantage is that it is inexpensive and effective. The disadvantage is that it may cause skin itching and flushing after taking even moderate doses. This effect is reduced by taking a single aspirin 30 minutes prior to the niacin.
Liver injury is also possible as with the statins and monitoring of liver function is recommended. Crystalline niacin does not seem to cause liver injury, which is primarily associated with long acting or slow release forms of niacin. Recent products that release niacin slowly to decrease the flushing are Niaspan, Slo-Niacin, Niocor and Nicolar, but require regular monitoring of the liver to detect early damage. Niacin doses of 200-400 mg per day may be effective in lowering cholesterol levels, while dosages of up to 2000 mg per day may be used in serious cases of elevated lipids. Niacin is available as a nutritional supplement without a prescription and is allowed by the FAA.
Bile Acid Sequestrants
Bile acid sequestrants act much like soluble fiber in the intestine. These products bind bile acids that allow dietary fat to be absorbed and processed into cholesterol. They have been on the market a long time. They are in powder form and may need to be mixed with juice to take in a palatable form. The major limiting factor is their tendency to cause stomach upset, bloating and flatulence. These side effects are minimized by gradually increasing the dosages. Bile acid sequestrants may also block the absorption of some medications. They may raise TG levels slightly. Examples include cholystramine (Questran) and colestipol (Colestid) and these are allowed by the FAA.
Gemfibrizol and Clofibrate
Fibric acid derivatives were some of the earlier triglyceride lowering medications. These medications are effective in lowering triglycerides, with much less effect on cholesterol. The major side effect is the potential for gallstones and gallbladder disease. Gemfibrozil (Lopid) or clofibrate (Atromid-S) have variable effects on LDL cholesterol. Use of gemfibrozil in combination with high dosages of the FDA recalled cerivastatin (Baycol) has been linked to patient deaths. Gemfibrozil used alone has not been associated with deaths. These are allowed by the FAA
Zetia (ezetimibe) is in a newer class of cholesterol and triglyceride lowering medication that can be used with other medications for the same condition. It’s mechanism of action is to selectively inhibit absorption of cholesterol from the small intestine, reducing uptake by 54%. This is allowed by the FAA.
FAA Reporting Requirements
The FAA will allow all medication categories listed above after a ground testing period of several days free of side effects. Reporting of the use of the medication is required at the time of the next FAA medical examination. Report in Section 17 of the FAA Application for Airman’s Medical Certificate, Form 8500-8, under Medications Used.
Controllers must report any prescription of over the counter medications to the Regional Flight Surgeon before returning to safety sensitive duty. Use of fiber, non-prescription niacin and nutritional supplements are not reportable to the FAA.
AMAS Aeromedical Assistance
For a more specific personal explanation to your questions or those concerning aeromedical certification, contact AMAS for a private consultation. For help in reporting treatment for and obtaining clearance from the FAA to fly or control with these conditions, refer to the AMAS FAA Confidential Question. If you are an AMAS Corporate Member, these services are FREE to you.