Active Low-Carber Forums - My thoughts on cholesterol, CHD, and LC...

I tend to believe in the Kendric theory of heart disease. Blood lipid abnormalities are a sign of disease, or perhaps a passive contributor to disease progression, but cholesterol itself is not the aggressive disease-causing agent it is currently perceived to be. Your body produces and uses cholesterol to repair cells. The cholesterol we have is almost entirely produced by the body, and its presence is totally normal and essential to life. However, sometimes it is observed that cholesterol is elevated and in an "unfavorable" ratio (low HDL/high LDL & triglycerides). These blood lipid abnormalities are correlated with incidence of CHD. This correlation has lead modern medicine to come to the conclusion that blood lipid abnormalities tend cause CHD. I think this is completely incorrect.

I tend to think the existence of blood lipid abnormalities is merely a sign that an abnormally high rate of cellular death/tissue decay is going on inside of you. The increased rate of cellular aging and death causes your body to elevate cholesterol in response, as your body needs more cholesterol for repairs. When damage is localized to the arteries - aged, damaged, hardened – they are "patched up" with the abundance of cholesterol produced by the body. This is the start of plaque formation and CHD. As the damage to the arteries increases, the plaques also grow too, eventually to the point where they compromise the integrity of the structure. This condition is called atherosclerosis, and it strongly poses a risk to health as it makes one prone to life-threatening blockages.

Should this theory hold up to be true, it would mean the blood lipid abnormalities are reactionary to not causative of CHD. It would also mean that the way we view CHD prevention is backwards; we are treating numbers when the number is only a symptom of disease, and the way we get the number lower may or may not also reduce disease risk. For example, sneezing is a symptom of being sick, but suppressing an urge to sneeze won’t necessarily prevent or cure the development or progression of the flu. Treating cholesterol numbers to prevent or control heart disease may or may not prove effective for the same reason.

Most importantly, should the theory hold true it would mean that something has to be damaging the arteries first for the disease to manifest, because cholesterol alone in absence of some sort of damage will not cause a plaque to form. So the more pertinent question seems to be what would cause arterial damage and decay? I think it can be said that the biggest risk factors are anything which would impair energy or oxygen utilization. Impaired ability to use energy and oxygen encourages general physiological decay, and the arteries are no exception. The two most prominent examples of risk factors for arterial decay are insulin resistance/impaired glucose tolerance/diabetes (which compromises the body's ability to use energy) and smoking (which likewise compromises the body's ability to utilize oxygen).

Why does LC work so well to improve blood lipid profiles? I think the reason blood lipids tend to improve on a low carb diet for some people is because for those people an underlying insulin resistance/impaired glucose tolerance was likely present. Once dietary macronutrient composition changes in favor of deriving energy from ketones (which require no insulin to assimilate by the body ) rather than sugar (which IRS people have varying degrees of difficulty in using) energy assimilation/utilization improves dramatically. When IRS people go on a high fat & low sugar diet, what is going on is for the first time in a long time they are effectively feeding the body energy. They will look and feel more healthy and energetic, and the pervasive state of physiological decay will stop progressing or even reverse itself (if early on enough.

This handily explains why many find an improvement in blood lipids on LC, but it doesn't explain why others may see a worsening in blood lipid profile. It’s rare, but it sometimes happens. I think those situations are a little more complex. An imbalance of dietary fats (too many of one kind, not enough of another), or an excessive consumption of fats damaged by oxidation (such as mono/polyunsaturates used in frying) or hydrogenization might play a role. Polyunsaturates in particular are highly reactive, which is why polyunsaturated fats should NEVER be used for cooking. Eating high quantities of even uncooked polyunsaturated oils, such as canola or corn, can result in vitamin e deficiency for this reason (vitamin e is a potent anti-oxidant, so demand for vitamin e increases when polyunsaturated oils also increase in the diet).

Though I think the reason CHD is an epidemic is largely attributed to both smoking & IRS, there may be other factors about our lifestyle which can cause or promote the disease. It is very premature to say ALL incidences of CHD are caused by IRS and smoking. Either way, I think it is fair to say that trying to get the number lower shouldn't be the main objective. Finding out why the numbers are poor in the first place and then treating the cause should be the main objective.