Cholesterol: The Facts Behind the Hype
Remember when almost every health story featured cholesterol as its subject, and everyone you knew was rushing out to have his or her cholesterol levels checked? Even as recently as a few years ago, we thought that having a low cholesterol level ensured long-term arterial health. We now know the story is more complex. Sure, it's generally good to have a low total cholesterol level, but many other factors are more important to ageing than cholesterol. In fact, most people who have cardiovascular disease have cholesterol levels below the 'high' marker of 240 mg/dl (milligrams per deciliter). Although high levels of total cholesterol and/or LDL (lousy) cholesterol can contribute to arterial ageing, other factors contribute even more: high blood pressure; cigar, cigarette, or passive smoking; not exercising; high levels of homocysteine; diabetes; and a diet that is heavy in fats and and poor in nutrients. Nevertheless, you should keep in mind that high cholesterol levels can affect your rate of ageing.
What Does 'High Cholesterol' Mean?
Cholesterol is a type of lipid (a fat soluble molecule) found in three places: in our cells, in our food ('dietary' cholesterol), and in our blood. As much as we fear cholesterol, it is a vital component of our bodies. Cholesterol is required for the body to manufacture hormones, build cell walls, and produce bile acids, which are essential for the breakdown and digestion of fats. In some areas of the body, cholesterol levels are high. For example, skin cells contain a lot of cholesterol, making them highly water resistant. This water resistance protects the body from dehydration by reducing the evaporation of water. The brain also has high concentrations of cholesterol.
When we measure cholesterol, we measure the amount of cholesterol circulating in the blood. Problems develop not from having cholesterol in the blood, but from having too much cholesterol and too much of the wrong type of cholesterol in our blood, where it can cause damage to our arteries. In general, having a high total cholesterol level is bad: Excess cholesterol can promote arterial ageing. However, even among such high-risk populations as middle-aged men, only 9-12 percent of those with total cholesterol readings of over 240 mg/dl will actually have symptomatic cardiovascular disease as a direct result of cholesterol. For each 1 percent increase in the overall cholesterol reading in middle-aged men (for example, for 202 versus 200 mg/dl), the risk of developing cardiovascular disease increases by 2 percent. High cholesterol levels affect different population groups disproportionately. For example, high cholesterol seems to have a significant ageing effect on young and middle-aged men, but a much less significant effect on older men and women of all ages. The female sex hormone oestrogen generally decreases the presence of cholesterol in the blood, whereas androgens—the male sex hormones—increase blood cholesterol. Premenopausal women rarely have to worry about their cholesterol levels.
The Ratio of LDL to HDL
Far more important than a person's total cholesterol reading is the ratio of his or her LDL to HDL. There are three basic types of cholesterol in your body: low-density lipoproteins (LDL), high-density lipoproteins (HDL), and very-low-derisity lipoproteins (VLDL). Because the VLDL level is rarely measured directly, in general, cholesterol tests measure total cholesterol, LDL, and HDL cholesterol. (LDL is calculated by subtracting HDL from total cholesterol.) LDL cholesterol causes ageing of the arteries; HDL cholesterol prevents it. (Recall that I remember the 'L' of LDL as 'lousy' and the 'H' of HDL as 'healthy.')
In general, a total cholesterol reading of 240 mg/dl is too high and can cause arterial ageing. In the most rigorous study on cholesterol, the Framingham Study, individuals with a cholesterol reading lower than 200 mg/dl had a 10 percent risk of coronary artery disease over a twenty-year period. Those with a total cholesterol reading above 240 mg/dl had about twice as much chance (20 percent) of developing the disease.
Most people who have high cholesterol also have high levels of LDL cholesterol, which causes arterial ageing. LDL molecules deliver cholesterol to the cells in the body. When cholesterol rises, excess LDL molecules in the bloodstream can attach to small ruptures or lesions in the arterial wall, the endothelium, and trigger a process that can lead to the development of arterial plaques and cardiovascular ageing.
It is interesting to note that some people with very high cholesterol levels have arteries that are in better condition than those of other individuals who have low cholesterol levels. These lucky people have high levels of HDL cholesterol and low levels of LDL cholesterol. Since HDL molecules remove excess cholesterol from the arteries, the more HDL you have, the less excess LDL cholesterol you have and the less arterial ageing you will undergo. Unfortunately, these people are the exception, not the rule.
When you get your cholesterol levels tested, make sure to ask not just for your total cholesterol level but for your total/HDL ratio. The lower the ratio, the better. The average ratio for middle-aged Americans is 5. It is calculated by dividing the number for total cholesterol by the number for HDL. For example, if you have a total blood cholesterol of 200 and your HDL is 40, the ratio is 5 (200/40). On the other hand, if your total blood cholesterol is 200 but your HDL is 57, your ratio is 3.5. A fifty-five-year-old man with a ratio of 3.5 would have only about half the risk of arterial ageing as the average man in his age group; his RealAge would be eight years younger. In contrast, if that man had a ratio of 9 (for example, 270 total/30 HDL), he would have more than five times the risk of arterial ageing as the average man in his age group; his RealAge would be twelve years older than average. Similarly, having either high LDL or a high LDL/HDL ratio can cause arterial ageing.
As mentioned, having a total cholesterol of over 240 mg/dl suggests a high risk of ageing. Likewise, a level of LDL cholesterol above 160 mg/dl or an HDL reading below 35 mg/dl correlates with an increased rate of arterial ageing. If your total cholesterol is more than 240, if your LDL cholesterol is higher than 160, or if your HDL cholesterol is lower than 35, you should talk seriously with your doctor about improving your cholesterol levels to retard arterial ageing. Having either high LDL levels or low HDL levels can make your RealAge anywhere from three to six years older. Having both high total LDL and a high LDL-to-HDL ratio can make your RealAge anywhere from six to eighteen years older, depending on the ratio. Even if your cholesterol status is more moderate—LDL levels above 100 but below 160 or HDL levels less than 55 but above 36—you should also consider taking steps to reduce your LDL cholesterol and increase your HDL levels.
Despite all the buzz about cholesterol-free foods, cholesterol is one factor that is largely determined by genetics. Genetics determine whether you have a tendency toward high LDL levels, and genetics largely determine your LDL-to-HDL ratio. That means that genetic factors gready determine how seriously you will be affected by arterial ageing caused by elevated LDL cholesterol levels if you don't adopt Age Reduction activities that are specifically targeted toward preventing arterial ageing. For example, if you are a man with a high LDL cholesterol level or a high LDL-to-HDL ratio and a number of your close male relatives died early from heart disease, you are at a high risk of the premature onset of cardiovascular disease (see Table 8.2).
As I mentioned, an HDL level above 60 mg/dl appears to provide tremendous protection against arterial ageing. Although some medications will help increase HDL levels, drugs are not the most effective way of improving your cholesterol ratio. In fact, no techniques have been proven to work for everyone. Exercise is one of the best ways to improve your HDL reading. Women tend to have higher HDL levels than men, and women are able to improve their HDL levels with exercise to a greater extent than men. A recent North Carolina study found that aerobic exercise increased HDL by 20 percent in female patients but by only 5 percent in male patients. Also, a glass of alcohol a night (half a glass for women) may increase your HDL level. For many people, losing excess weight improves their HDL readouts. Although the interaction between weight gain and cholesterol levels is still not well understood, the correlation between the two is strong.
In contrast, if you have low LDL cholesterol, your genetics are protecting you from arterial ageing. Finally, there are a lucky few who have high total
[Soybeans as Youth Beans - Recent studies have linked soy protein to a reduction in levels of LDL cholesterol. People who regularly consume soy products—soy milk, tofu, and soy beans (and that doesn't mean soy sauce!)—have LDL cholesterol levels that are, on average, 13 percent lower than those who don't. Try substituting soy-based products for animal protein in your diet. The consumption of soy products may have a particularly big impact on those with very high cholesterol levels. It is not clearly understood why or how soy protein helps reduce cholesterol levels, although some experts theorize that the soy works as an antioxidant on cholesterol. Others think that soy may interfere with the formation of plaque. To make a substantial difference in cholesterol, you would need 31 to 47 grams of soy protein a day. Soy also contains a natural oestrogen that has been shown to reduce the risk of both breast and prostate cancers and to provide extra protection for ageing of the bones] The very important fact is you have to make sure the soy product is organic and not GM - genetically modified in any way - Keith Hunt
cholesterol and high HDL cholesterol. These people have a genetic trump. All that HDL cholesterol helps protect them from arterial ageing. They can have a RealAge as much as twenty-six years younger than their cohorts.
How to Reduce Cholesterol Levels
Since there has been so much focus in the media on eating a 'low-cholesterol' diet, it is surprising to learn that eating a low-cholesterol diet is not an especially effective way to reduce LDL cholesterol. Cholesterol consumed in food will cause a rise in cholesterol levels for some people and will have no effect on other people. Only 15 percent (one in seven individuals) who try a low-cholesterol diet get a significant antiageing effect from doing so. Again, genetics play a role: Genetic factors largely determine your sensitivity to dietary cholesterol, and people can range from extreme sensitivity to complete insensitivity. A person who has a genetic insensitivity may consume as much as 1,000 mg of cholesterol daily without negative consequences. In general, though, it is recommended that you consume less than 300 mg of cholesterol a day. People who show a particular sensitivity to dietary cholesterol should eat even less than that to retard or reverse arterial ageing. How do you know your responsiveness to dietary restriction of cholesterol? Only by measuring blood levels before and after restricting dietary cholesterol. A dramatic decline suggests that you are sensitive. A more modest decrease of 10-15 percent suggests that you are not.
For most of us, consumption of fat influences our levels of cholesterol in the blood far more than consumption of cholesterol itself. Unless you are especially sensitive to dietary cholesterol, your body produces almost all the cholesterol that exists in the bloodstream. The liver manufactures cholesterol from the saturated and trans fats you consume. This is yet another reason why it is important to eat a diet low in saturated and trans fats.
The best way to reduce high LDL cholesterol is to choose foods that are low in cholesterol, saturated fat, and trans fat. If you have high LDL cholesterol, you may want to consider taking medicine to reduce those levels. Talk to your doctor about getting a more extensive lipid evaluation and about the pros and cons of medication for improving either your overall cholesterol level or your LDL-to-HDL ratio......
Triglycerides are lipids (fats) that circulate in the bloodstream. Triglyceride measurements are usually taken after an overnight fast and when cholesterol levels are analyzed. The average fasting triglyceride level is 120-125 mg/dl. Levels above 200 mg/dl are associated with significant arterial ageing, especially with plaque buildup along the arterial wall. Since triglyceride levels fluctuate a fair amount, people with high levels (above 190 mg/dl) will want to have their blood analyzed several times to get an accurate estimate. If your fasting triglyceride level is above 200 mg/dl, reduce total fat intake. Cutting saturated and trans fats to less than 7 percent of your total caloric intake, eating fish rich in omega-3 fish oils at least three times a week or more, and increasing your physical activity are all actions to choose before considering possible drug therapies
Low Cholesterol Levels
With all this talk about high LDL cholesterol, do we have to worry about the other side of the spectrum? Can your cholesterol level dip too low?Apparently, yes, although we know far less about ultra-low cholesterol than high cholesterol, as very few people without an acute disease or chronic malnutrition have cholesterol levels low enough to be of concern. In a few but not all studies, people with low total cholesterol levels appeared to have a higher incidence of cancers and, curious to note, suicides. Although very few studies have been done on this subject, and we still cannot say with any certainty how low 'too low' is, it appears there is some risk. A possible explanation for the relationship to cancer may be that cholesterols are necessary components of vitamin D3, a proven cancer fighter. As for the suicides, no one really knows. Cholesterols are important in the functioning of brain cells and the production of hormones, so an ultra-low level of cholesterol may affect these two functions.
TO BE CONTINUED