I'm a scientist, so bear with me while I wax scientific for a minute. There is currently no evidence that the elevated cholesterol with protease inhibitor (PI) use derives from increased formation of cholesterol in the body, or from dietary intake. We know that PIs interfere with cytochrome P450 enzymes. It is a section of this class of enzymes that convert (with help from vitamin B3) cholesterol to bile acids/salts, a major mechanism for removal of cholesterol from the body. It is reasonable to assume that many drugs, including PIs, inhibit this conversion, resulting in excessive buildup of cholesterol in the body. A wealth of evidence indicates many of the adverse effects (gastro-intestinal problems, essential fatty acid defects, imbalance in testosterone and its dihydro form, etc.) of multiple drug regimens derive from interference with P450 enzymes (CYP11, CYP17, CYP19 and CYP21), especially those enzymes of the adrenals, testis and ovaries. Unfortunately, this particular group of P450 enzymes seems not to be examined by pharmaceutical companies in their testing procedures. Indeed, there has been little research in this area regarding drug use.

If, for whatever reason, both TGs and cholesterol are elevated, it would seem wise to "pull out all the stops", and not to gamble. Coconut fat, in this case, would best be avoided. Also, since ritonavir carries the greatest likelihood of P450 interferences, it may be wise to minimize saturated fat intake as a prophylactic measure with this PI (perhaps to slow the onset of elevated TGs &/or cholesterol). Otherwise, coconut fat can be an easy source of calories that bypasses the carnitine pathway. But, we must first ensure adequate intake of the essential fatty acids (both n3 and n6 types commonly known as Omega-3s and Omega-6s).

Use of monounsaturated fats such as found in olive and canola oils would be a good choice for the major dietary fat intake after the essential fatty acids. Indeed, canola oil, but not olive, will supply the essential fatty acids as well as monounsatured fat, while being a low contributor to saturated fats. Avoidance of high intakes of the trans fats may be more important than avoidance of saturated fats, though we don't have enough information yet to make a definitive informed decision. (Trans fats, by the way, are found in hydrogenated forms of unsaturated oils, common in margarine and a variety of baked goods [read the labels]. Saturated fats cannot exist in a trans form, so there is no worry of trans forms from them.) Several servings per week of fresh fish (which are a good source of the Omega-3s) would also be a good way to moderate buildup of TGs and cholesterol. Supplements of fish oil may be okay provided trans fat contents are low. Processing (such as deodorization) of fish oils may form higher levels of trans fats than are formed by the processing of vegetable oils (like flax seed), and because of this I am leary of general recommendations for use of fish oil supplements. The fish itself is better.

Thus, while encouragement of coconut fat as a high proportion of dietary fat intake was reasonable before HAART (Highly Active Anti-Retroviral Therapy) programs, I think this fat should now be used with caution and discretion by those taking combinations of several drugs that interfere with P450 enzymes. Although there are no compilations of drug-drug interactions for the P450 enzymes that are in question here, an indication of potential interactions is available from tables for other P450 enzymes (especially, the CYP3A4, CYP2D6 and CYP2C9/19 enzymes of the liver) available at hivinsite.ucsf.edu. Perhaps of equal concern is that there are no tables for relevant drug-food interactions. Unfortunately, food components such as common bioflavonoids (quercetin, also called quercitin, is the most common, but there are others) that would otherwise be expected to be beneficial for cholesterol control, may be major sources of drug-food interactions.

As with most of human nutrition, few recommendations are possible from proven facts. We are left to rationalize "reasonable recommendations" from available information. It is important to keep one's ear to the ground for further information.

Diana Peabody, RD responds:

A further comment on this question. Saturated fats do not have to be avoided altogether but can make up about 10% of calories (for a man who gets about 2500-3000 calories this means about 25-30 grams of fat from saturated fat per day). Some of this could be from the coconut fat. Trans fatty acids also need to be limited and are likely as bad as saturated fats ( maybe worse) for increasing the risk of cardiovascular disease. These are found in hydrogenated oils which should be on the labels of foods. Common ones are snack foods, margarine, crackers, some peanut butters. It is worth reading the labels for this one.