When did cholesterol get so complicated? Not too long ago, there was just “bad” LDL cholesterol and “good” HDL cholesterol.
Now it appears that LDL cholesterol isn’t necessarily bad in and of itself. In fact, it is needed to produce hormones. Turns out, it is only when LDL cholesterol becomes oxidized (think inflamed or even rusted) that problems can occur. It’s this type of oxidized stress that can lead to heart and circulation issues.
In a new study, Canadian researchers looked at whether high cholesterol-induced oxidative stress was similar across three different organs (heart, liver and kidney), and if vitamin E could slow its progression.
Cholesterol, Oxidation and Vitamin E
To determine the relationship between high cholesterol-induced oxidation, vitamin E, and three different organ groups, researchers divided 24 rabbits into four groups:
1. Regular diet for two months
2. High-cholesterol diet for two months
3. High-cholesterol diet for four months
4. High-cholesterol diet for two months, followed by a high-cholesterol diet plus vitamin E supplementation for two additional months (four months total)
Blood samples were taken from all animals at the start of the study, after two months, and again after four months to test for total cholesterol. Additionally, at the end of the study, the rabbits were anesthetized and the hearts, livers and kidneys were tested for malondialdehyde (MDA) — a biomarker for oxidative stress — as well as chemiluminescence (CL) — a measure of oxidative stress and antioxidant reserve.
An increase in MDA would indicate elevated oxidation, while an increase in CL would indicate depleted antioxidant levels, which in turn, points to increased LDL oxidation.
Vitamin E is a True Anti-Oxidant
After two months, researchers found that cholesterol levels were lower in the first group as compared to the other groups. After four months, cholesterol levels in groups three and four were the same as those in month two, but higher than at the start of the study.
When it came to heart health, researchers found that MDA levels were higher in the last three groups as compared to group one. But group four (the vitamin E group) only had a 2.42-fold increase, while the two-month cholesterol diet saw a 3.16-fold increase. The four-month cholesterol diet had a whopping 14.65-fold increase. This indicates that the vitamin E reduced the MDA in the heart by more than 83 percent.
As for CL, all groups saw similar levels, except for group three, which was 13.38 percent lower. This suggests that the antioxidant reserve didn’t change until high cholesterol levels were maintained for a longer period of time. It also shows that vitamin E helped to keep antioxidant reserve at “control” levels, even in the face of a prolonged high-cholesterol diet.
In the liver, MDA levels were similar in groups one, two and four, but were 218 percent higher in group three (as compared with group one). Interestingly, group four’s levels were 54 percent lower than those in group three. This suggests that it takes a bit longer for liver MDA levels to indicate oxidation, and that vitamin E helps reduce MDA levels.
When it came to CL, levels were 66 percent lower in group two as compared to group one, and 95 percent higher in group three as compared to group one. Groups four and one had similar levels. This indicates that, once again, vitamin E increased the antioxidant reserve.
Lastly, in the kidneys, MDA levels increased in groups two through four as compared to group one. They increased 273.5 percent in group four, 454 percent in group two, and 953 percent in group three. Given this, it appears that vitamin E reduced MDA levels by up to 71 percent. Vitamin E didn’t appear to have any effect on CL levels in the kidneys.
In reviewing the results as a whole, researchers concluded the following:
1. A high-cholesterol diet did, in fact, raise total cholesterol levels.
2. High cholesterol levels cause oxidative stress in the heart, liver and kidneys.
3. The heart is the most susceptible to oxidative stress, while the liver is the least.
4. The longer that cholesterol levels were elevated, the greater the oxidative stress.
5. Vitamin E appears to slow the progression of oxidative stress.
Boost Vitamin E Levels
While we are clearly not rabbits, this study does provide solid evidence that a high-cholesterol diet is bad for us and that vitamin E is good for our hearts… and livers and kidneys.
In addition to avoiding trans-fat and processed foods that can send your cholesterol levels through the roof, up your intake of vitamin E-rich foods. These include wheat germ oil, sunflower seeds, almonds, hazelnuts, peanuts, olive oil, spinach, mangoes and tomatoes.
If you want an extra surge, you can supplement with natural vitamin E (indicated as d-alpha tocopherol, as opposed to dl-alpha-tocopherol, which is synthetic). Aim for 500 to 1,000 mg (up to 1,500 IU) per day. If you’re looking for a high-quality vitamin E supplement, you can click here.
 Prasad K et al. Vitamin E slows the progression of hypercholesterolemia-induced oxidative stress in heart, liver and kidney. Mol Cell Biochem. 2012 Sep;368(1-2):181-7. [Epub 2012 Jun 20.]