Cardiovascular researchers have long known that: 1) Persons with diets high in saturated fat often have high levels of LDL cholesterol; the bad cholesterol and 2) Persons with high LDL often develop cardiovascular disease. To find ways to fight the disease, a group of researchers recently conducted an experiment to determine whether these correlations are coincidence or cause. They discovered mechanisms by which a saturated fat-rich diet may increase the transport of cholesteryl esters from LDL into the cells lining arteries. To see the article that describes this research, click here. "Saturated fat-rich diet enhances selective uptake of LDL cholesteryl esters in the arterial wall." J. Clin. Invest. 115:2214-2222 (2005). doi:10.1172/JCI24327. This Research Update column highlights articles related to recent scientific inquiry into the process of human aging. It is not intended to promote any specific ingredient, regimen, or use and should not be construed as evidence of the safety, effectiveness, or intended uses of the Juvenon product. The Juvenon label should be consulted for intended uses and appropriate directions for use of the product.

By Benjamin V. Treadwell, Ph.D.

Seared to a crisp, golden brown, the fat on the edge of a steak can be quite flavorful. Since it tastes so good, however, we intuitively realize it’s probably not good for us.

The common belief that fat is bad has been challenged in recent years by a number of individuals, most notably the late diet guru, Dr. Atkins. There was good reason for this challenge, as no one could unequivocally demonstrate a biochemical basis to support this "fat is bad" doctrine. Dr. Atkins correctly pointed out that early explanations for this doctrine were rather naïve, including the common one that stated the greasy, insoluble fat literally clogged our arteries. To most of us that made sense; it is greasy, water-insoluble, and sticks to everything, so clogging an artery was easy to understand. The real story, however, is more complex.

Not All Saturated Fats Are Equal

It turns out that this type of fat is found not just in steaks, but also to varying degrees in butter, vegetable, palm and coconut oils, and milk-chocolate bars. It is commonly referred to as saturated fat. But wait — not all saturated fat is equal. There are different types of this fat, each causing very different biochemical effects on our tissues. Nevertheless, saturated fats were grouped together as one bad guy.

How are saturated fats different from one another?

Saturated fats are distinguished from each other by their length, which is proportional to the number of carbon atoms they contain. In most naturally occurring saturated fats, the length ranges from 12 to 24 carbon atoms. One of the saturated fats quite prevalent in steak (stearic acid) is 18 carbons in length. This fat is benign, in that it has little effect on our cholesterol levels. However, saturated fats with 12, 14, and 16 carbons atoms, when ingested in significant quantities, cause an increase in our bad (Lousy) cholesterol, LDL.

How does some saturated fat promote ill-health?

One of the saturated fats that has a negative effect on our health when ingested in significant quantities is the 16-carbon variety, also known as palmitic acid. This fat has been shown in human studies to inhibit the conversion of fat to energy, and thus to slow down energy expenditure….an undesirable effect, especially if one is overweight. Furthermore, this palmitate-induced inhibition of the conversion of fat to energy may increase one's chances of developing diabetes, since it promotes obesity.

Recent studies reveal a more disturbing effect of this type of saturated fat on the development of diseased arteries (atherosclerosis). These studies demonstrate that saturated fat, combined with elevated blood-cholesterol, especially high LDL cholesterol, increases the uptake of disease-producing cholesterol esters by cells lining the walls of the arteries. In these cells, large quantities of cholesterol esters initiate an inflammatory response, resulting in subsequent plaque formation, hardening of the arteries, and development of high blood pressure.

Thus the controversial "fat is bad" doctrine is now beginning to unravel. Not all saturated fats are equal. It is not one bad guy involved in the disease-producing events, but at least two….the combination of high levels of both LDL and a particular saturated fat.

So, how can we keep our saturated fat down to a healthy level?

Since the saturated fat story is far from complete, and since no one food contains only one type of saturated fat (the benign and bad saturated fat are found together), it is most appropriate to keep high "sat-fat" foods to a minimum. It's best to follow the Mediterranean diet, which prescribes a nutritious diet with low saturated fat (< 8% of total calories). Marbled steak is very high in saturated fat, so if you are having steak, go for the grass-fed, lean cut containing less of the LDL-raising saturated fat.

It is not a good idea to substitute a high carbohydrate diet for a low meat diet, as the former can actually promote the synthesis by our cells of saturated fats. It is far more reasonable to add protein to your diet from a source containing low saturated fat, such as fish, chicken, whole wheat products, vegetables, fruits and legumes. The total calories/day should be about 30-35% fat, 25-30% protein, and 40% from carbohydrates.

Olive oil can counter the effect of saturated fat.

No one is asking us to completely eliminate the bad saturated fat from our diets, but there are ways to help prevent the destructive actions of these fats. Monounsaturated fat, such as oleic acid present in olive oil, sunflower oil, avocados, and other fruits, has the remarkable effect of countering the negative health effects of saturated fats such as palmitic acid. For example, oleic acid speeds up the conversion of fat to energy, and thus neutralizes the inhibitory effect of palmitic acid on fat metabolism. Furthermore, the palmitic acid-stimulated uptake of cholesterol into cells can be inhibited by increasing the amount of oleic acid in your diet. It appears that the oleic acid present in olive oil interferes with the uptake of toxic cholesterol esters by the cells that line the arterial walls.