My brother-in-law had mentioned last Thanksgiving that after eating a big turkey meal, one frequently feels very tired, and wondered if some aspect of nutrition could be explored in this regard.
As I began to think about it more, I thought this would be an excellent time to discuss the effects of cardiovascular disease after eating a big meal. I recall quite vividly, as a medical resident back to the 1970s, about seeing many patients in the emergency room after a festive dinner.
As it turns out, there was a recent article in the medical literature discussing the post-prandial effects (meaning “after eating”) of dietary anti-oxidants in humans. The article discusses that traditional risk factors are typically measured in individuals in a fasting state, but this, in point of fact, only predicts half of the actual cases of cardiovascular disease. There are many complex and harmful reactions that occur after eating.
The article notes that the consequences of the reactions of oxidation that occur after eating represent major risks for fatal and non-fatal heart disease and stroke. (“Oxidation” is the process in which fatty acids are broken down). It has been well reported that after eating, oxidative modifications occur to LDL cholesterol (“bad” cholesterol), along with a reduction in the production and activity of nitric-oxide, and overall reduction in endothelial (the lining of blood vessels) function.
The article goes on to say that supplementation with anti-oxidants may prevent or reduce many of these risk factors. In many studies, anti-oxidants have been shown to reduce oxidative damage to LDL cholesterol, improve the bio-activity of nitric-oxide, prevent glucose auto-oxidation (the direct combination of any substance, in this case, glucose, with molecules of oxygen at room temperature), and prevent or lessen the decrease in endothelial function associated with the post-prandial state.
A classic study about endothelial function was reported in the Journal of the American Medical Association (JAMA) back in 1997. In this study, twenty healthy individuals with normal cholesterol were randomly assigned to eat three different breakfasts:
- (1) a high fat meal containing 50 g of fat;
- (2) a low fat meal with 0 g of fat; and
- (3) a high fat meal, this time pre-treated with oral administration of 1000 mg of vitamin C and 800 units of vitamin E. At the end of each meal, blood flow through the brachial artery in the arm was measured.
After eating the high fat meal, the first group had a reduction in blood flow in the arm up to 28%, with persistent restriction of blood flow for the next four hours. No significant changes were noted in blood flow after eating the low fat meal.
Those individuals who were pre-treated with vitamin C and vitamin E and then consumed the high fat meal also did not have any reduction in blood flow through the arm. The study concluded that a single high fat meal temporarily reduces endothelial function for up to four hours in healthy, normal, cholesterolemic (relating to cholesterol) individuals.
This is thought to be caused by the accumulation of triglyceride-rich lipoproteins. In addition, this decrease in blood flow is blocked by pre-treatment with anti-oxidants, specifically vitamins C and E, thus suggesting a process involving oxidation.
The implication of this is extremely significant. There are tens of thousands of people in this country who suffer from fatal heart attacks and strokes every year during the holiday season, presumably, as a direct result of eating an excessively high fat meal. Adequate doses of anti-oxidants may very well reduce this effect. If any of you think that you are being adequately protected with your once-a-day vitamins, think again. The quality and quantity of anti-oxidants and nutrients in these vitamins are far from adequate.
On many occasions in the past, I have cited an epidemiologic study conducted by the Centers of Disease Control several years ago. Over 1.1 million Americans were followed for seven years in this study, and those individuals who took a typical once-a-day vitamin did not have any reduction in mortality from cardiovascular disease, compared to individuals who took no vitamins at all. It was not until those individuals took supplemental vitamins C and E that there was any improvement in cardiovascular mortality.
References & Further Reading: