Friday, February 17, 2012

The Cholesterol Conundrum (part 3) - Statins

In our first two posts on cholesterol, we discussed the flawed research that created the myth that cholesterol and dietary fat cause heart disease. We also discussed the role that cholesterol actually plays in the body. With these pieces in place, we can discuss what, if any, benefit can be gained by taking cholesterol lowering drugs called “statins”.

Statin drugs are among the most widely used and studied pharmaceutical drugs of all time. They are primarily prescribed to lower cholesterol levels in people who are considered at risk of developing cardiovascular disease. But, due to the confusion around cholesterol, many people who only have slightly elevated cholesterol and no other risk factors are being prescribed statin drugs. Statins are the number one prescribed class of drugs in the developed world and yet this “miracle drug”, has not improved the amount of heart disease, in fact, heart disease continues to go up despite the massive number of statins being prescribed. 
Why is this so? The real question is, do statins actually help prevent heart disease or any other health problems? If they don’t, then what are risks of taking statins and are they actually as safe as the manufacturers would have us believe?


Many people who have “elevated cholesterol” levels are prescribed statins. As we have discussed in our previous posts on this topic, not all cases of elevated cholesterol are the same. Only a very specific type of very small LDL cholesterol (type B LDL) is actually of concern for heart disease. Therefore, many people who are told that they are “at risk” of developing heart disease simply because of elevated cholesterol may not actually be at risk.

WHAT DO STATINS DO?

Statin drugs work by blocking an enzyme called “HMG-CoA reductase” in the liver. Levels of this enzyme are what determine how much cholesterol you can make. HMG-CoA is what is known as a “rate limiting” step in cholesterol production (which means that if you stop HMG-CoA reductase from working in your body, you prevent cholesterol production). So by preventing HMG-CoA reductase from being able to assemble cholesterol, you can limit the amount of cholesterol produced overall. But lowering levels of cholesterol isn’t necessarily a good thing, as we discussed in our article on what cholesterol actually is and how essential it is for our bodies.

FLAWED RESEARCH

The research on statins simply does not support the idea that lowering cholesterol (by taking statins) actually helps with preventing heart disease in most people. This is primarily because statin drugs don’t change the part of the cholesterol that matters, the LDL size. Statins simply reduce the total amount of cholesterol available to be made into lipoproteins, but that doesn’t do anything to actually change the makeup of these lipoproteins. If statins could selectively decrease the amount of small type B LDL, while leaving all the other lipoproteins unchanged, this might be helpful in the prevention of heart disease. But this is NOT what statins actually do. When it comes to heart disease, it isn’t really the total amount of cholesterol or even the total amount of LDL cholesterol that matters, but the type B LDL which gets stuck in arteries, leading to atherosclerosis.

WHEN STATINS MAKE SENSE

For certain patients (especially men) who have a history of cardiovascular disease, studies do show a small benefit from statins preventing future heart related problems (e.g. heart attacks). However, it is now thought that this protective action has less to do with cholesterol than the other beneficial effects of taking statin drugs.

RISKS OF TAKING STATINS

Then there are the serious side effects associated with statins. While the chance of side effects is relatively low, the number of people taking statin drugs is so high (well into the hundreds of millions worldwide) that this can become a real public health concern. In other words, while serious side effects may occur in only a small percentage of people taking statins, the actual number of serious side effects in people taking statins still involves thousands if not millions of individuals. Obviously, taking statins without any clear benefit to your long term health may not be something you want to risk, especially when you learn about the nature of the side effects.

Side effects:

Muscle damage is a particularly bad side effect that some patients can experience while taking statin drugs. When this happens, muscle tissue starts breaking down, and the damaged proteins from this are removed through the kidneys. While relatively rare, this excess protein from the muscle damage can overwhelm the kidneys and can lead to a disease called rhabdomyolysis. This can cause significant damage to the kidneys and even kidney failure. If you may not even get any of the advertised benefit from taking statins, why would you want to risk kidney failure and possibly even dialysis? It just doesn’t make sense.

Kidney damage from statins can make
dialysis or even kidney transplants
necessary.
As we mentioned before, statins work by inhibiting the function of the HMG-CoA reductase enzyme. While you might imagine that HMG-CoA reductase is only involved in making cholesterol, this is not the case, this enzyme affects other processes in the body as well as cholesterol production. For example, this enzyme is also used by your body to make Coenzyme-Q10, which is vital for production of energy (ATP) in the mitochondria of cells. Ironically, this can cause serious issues for people who have severe heart problems and worsen heart function in patients with a history of heart problems. Is this what you want when you are taking a drug to try to help you prevent heart disease?

There are also side effects that happen in the brain. Lowering the amount of total cholesterol available for your body by taking statin drugs can damage your brain because your brain uses a large amount of cholesterol during development and even for normal day to day function. So, it should come as no surprise that lower levels of cholesterol can cause an impact on brain function. In fact, several studies have shown brain related side effects in people taking statins, including memory loss, severe irritability (e.g. homicidal impulses, threats to others, road rage, etc.) as well as cognitive impairment.

Finally, many other problems are related to reducing your levels of cholesterol with statin drugs. These can include erectile dysfunction and polyneuropathy (where nerves start to malfunction). In addition, statin drugs tend to increase the chances of developing diabetes, with higher doses making this more likely.

People over the age of 80 are particularly succeptible to the side effects of statin drugs. Even in people who have a history of heart disease and elevated cholesterol, the side effects are considered so dangerous that statin drugs are specifically not recommended to this group of people.

BOTTOM LINE

While statins may be useful in treating a small subgroup of patients who have had previous heart attacks, most people taking them don’t fall into this category. Statin drugs, though useful for some people, have some serious potential side effects. In addition, statin drugs have not been demonstrated to significantly reduce the likelihood of heart disease in people who only have high cholesterol but no history of heart disease. Some benefit has been demonstrated, however, for people who have had previous heart attacks and who still have elevated cholesterol levels.

If you find out that you have high cholesterol, but have no history of heart disease, then dietary changes and regular aerobic exercise appear to be, by far, the best method of preventing heart disease from developing. Eating a diet rich in phytosterols and avoiding carbohydrates or sugar goes a long way toward lowering levels of LDL-B in your body. Avoiding sugar and carbohydrates also prevents a huge source of dietary free radical production. Regular exercise and eating a diet with more protein and fat (with the exception of trans-fat) helps to increase levels of HDL, which is associated with health benefits.

The ratios of cholesterol and lipoproteins are not what cause heart disease. Unfavorable levels of cholesterol develop because of diet and lifestyle choices which themselves are unhealthy for your heart. Eating large quantities of sugar or carbohydrates puts a strain on your body, causing free radical production. A sedentary lifestyle and lack of aerobic exercise lowers the levels of HDL production, further exacerbating the problem. Both poor diet and lack of exercise lead inevitably to insulin resistance, diabetes, obesity, and an even greater risk of heart disease. If it were as simple as one factor leading to an increased risk of heart disease, then combating heart disease would be easy, but heart disease is more complex than that. Unfortunately, statin drugs are not the “miracle” drug that their manufacturers would have us believe, and may do more harm than good in some people.

I think one of the main problems we are facing with statins is that they are being over-prescribed to people who are not necessarily at risk. Perhaps, someday when it becomes routine to start measuring the levels of LDL cholesterol that matter in heart disease (type B LDL), we may find better ways to identify those people who are most at risk of developing heart disease who may be helped by statins. On the other hand, since type B LDL cholesterol decreases simply by decreasing sugar and carbohydrates from the diet and performing regular aerobic exercise, I have to wonder if statins will ever be found to be a particularly valuable option.


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Researched and written by Dr. Rebecca Malamed, M.D. with assistance from Mr. Malcolm Potter.

1 comment:

  1. Thanks for raisina concern about a misconception people had about the use of Statins and its effects. I really appreciate your effort here.

    ReplyDelete