QuestionDear Sarah,
I actively study nutrition & health on my own through textbooks like "Understanding Normal & Clinical Nutrition 7th Ed" & research on the Net health-related topics. I have a question regarding saturated fats & heart disease :
We have all been told for decades that eating saturated fats increase the risk of contracting heart disease & cancer because it increases our cholesterol levels in the blood (particularly LDL-the bad cholesterol). And to instead embrace non-saturated fats like mono & poly unsaturated fats as healthier alternatives.
This has been the mainstream advice from nutrition & health "experts" for a long time. However, I have read that it isn't so much cholesterol that is the culprit for heart disease & cancer, but rather the susceptibility of LDL cholesterol to become oxidised by free radicals & thereby starting a chain-reaction of free radicals that destroys DNA, cells, etc in the body. I've come to understand that LDL cholesterol by itself is neutral & not harmful to health. LDL cholesterol has many beneficial uses for the body. It only becomes, when it gets oxidized.
Saturated fat by it's chemical structure is much more stable & resisant to oxidation than mono-unsaturated fat & mono-unsaturated fat is more resistant than poly-unsaturated fat to oxidation. Also, about 50% of body cells are composed of saturated fat, while 38% is mono-unsaturated fat & only 12% poly-unsaturated fats. Could the shift from saturated fats (traditional healthy diets) to vegetable cooking (poly-unsaturated)oils (processed foods of modern commerce) in our diets be the cause of heart disease & cancer since they oxidise much easier?
Also, there are saturated fats like red palm oil & coconut oil which are bursting with vitamins, phyto nutrients & anti-oxidants. Recent studies have shown the cholesterol lowering effect of red palm oil & also it's ability to scavenge free-radicals because of the mixed toco-trienols in red palm oil, which are 60 times more potent & destroying free radicals than toco-pherols.
What about mounting evidence that the amino-acid homocysteine may play a bigger role in heart disease than saturated fats?
Thank you for your reply & looking forward to your answers.
AnswerI am sorry I took so long to answer, Andrew, but I wanted to think about how to answer you. I will tell you what we have been taught in class about fats is pretty limited, along the lines of: saturated fat bad, cholesterol bad, trans fat worse, and unsaturated fat better with omega-3 fats being good. We were taught LDL contributes to heart disease not because it is oxidized but because it is lighter in weight than HDL and gets caught in cracks in the blood vessels easier. We were taught unsaturated fats are better because they are not as stiff and stable as saturated fats and, therefore, are not caught in cracks in the vessels as easily. We were also taught unsaturated fats can act as antioxidants by accepting free radicals and becoming oxidized themselves, reducing the risk of blood lipids becoming oxidized. That kind of goes with what you mentioned about unsaturated fats being more readily oxidized; they are, but the theory is by them becoming oxidized elements necessary to your body are not oxidized. We were actually taught nothing about fat and cancer; at best, it was suggested higher fat foods replace more cancer-preventing foods such as fruits and vegetables in the diet.
I do not believe the suggestion to use unsaturated fats has led to the increase in heart disease and cancer for two reasons. (1) Many traditional diets, including the Japanese and Mediterranean diets, are much higher in unsaturated fats than saturated fats and they have much lower rates of both heart disease and cancer. If your theory is true and unsaturated fats contribute more to heart disease and cancer than saturated fat, it could be off-set by their higher intake of fresh fruits and vegetables. However, studies have shown (with the exception of France), countries who eat higher amounts of animal products have higher rates of both heart disease and cancer. I have read articles in vegetarian magazines which attribute the rates to too high of an intake of vitamin B12 and not saturated fat, but I have never looked for studies on the subject. Also, studies have shown people with heart disease and/or high cholesterol who make an effort to increase the DHA/ALA (types of omega-3) in their diet can actually reverse damage and improve labs without medication. (2) Many other factors in the environment have changed besides nutrition experts suggesting unsaturated fats. For decades, unsaturated fats were hydrogenated (and still are in much smaller amounts) and trans fat definitely has a link to heart disease. People have become more sedentary and eat less fiber, both of which have been linked to heart disease. Portion sizes have increased and studies have shown not only more free radicals with overeating but also more stress on the body to metabolize all the food. That抯 not to mention all the chemicals we are exposed to every day that were not common even 10 or 20 years ago. In fact, I was just reading the other day about studies on the chemicals in plastic which suggest they contribute to obesity (which you know has been linked to heart disease); think of all foods we buy in plastic containers that were in glass or paper even just a few years ago!
In answer to your question about coconut and red palm oil, they are saturated fats but they are medium chain fatty acids while saturated fats in animal products are long chain fatty acids. That is a significant difference because the human liver breaks medium chain fatty acids down easier and they are less likely to enter the bloodstream in their saturated state.
Finally, a link has been shown between homocysteine levels and heart disease; however, the test is expensive, and not usually covered by insurance, so more often cholesterol levels are used by doctors (with triglycerides appearing to be the most accurate for predicting future cardiovascular problems). Ironically, studies have shown homocysteine levels can be reversed by (this sounds like a broken record) eating more fruits and vegetables, even if meat consumption is not reduced.
I am sure that is not as detailed as you were looking for, but I hope it gives you more to think about. Good luck with your studies!
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