News & Reviews

Vitamin E Supplements--Good for Heart Health?

by Michael Reynolds, Pharm.D. Candidate, St. Louis College of Pharmacy

There has been much attention lately in the media regarding the benefits and harms of vitamin E supplementation to prevent heart disease. Although vitamin E was once thought to be beneficial for the prevention of cardiovascular disease, recent studies have found that this may not be the case. Therefore, the medical community has recently recommended against using vitamin E for cardiovascular disease prevention. On the other hand, the supplement industry still believes that vitamin E has a place in therapy. Who is the consumer to believe? Let's start from the beginning.

What is cardiovascular disease and why has vitamin E been used for its prevention?

Cardiovascular disease is a condition that can result when fat and cholesterol build up in the arteries (also known as atherosclerosis). This build up--or atherosclerosis--may eventually block the flow of blood and cause a heart attack or a stroke.

The type of cholesterol that is mainly to blame is low-density lipoprotein (LDL) or "bad cholesterol." When LDL cholesterol is elevated, it increases a person's risk for developing atherosclerosis and cardiovascular disease. According to the American Heart Association, cardiovascular disease is the leading cause of death in the United States with approximately 36% of deaths in 2004 caused by it.¹ Therefore, it is important to take a preventive approach to cardiovascular disease including living a healthy lifestyle; eating a healthy low fat, low cholesterol diet; and for some individuals, taking a daily low-dose aspirin (81mg - 325 mg).

Keeping the build-up of LDL cholesterol at bay is also important. Everyone has LDL cholesterol in their body. But, when excess LDL cholesterol is present, that's when risk for cardiovascular disease is increased. A process called "oxidation" occurs in the body which causes LDL cholesterol molecules to deposit and stick inside blood carrying arteries. After time, arteries can clog and blood flow can become reduced or blocked all together. So, years ago, scientists started to look for ways to stop the "oxidation" process, which would then in theory hinder LDL cholesterol molecules from building up inside arteries and thus reduce the risk for developing cardiovascular disease.

Vitamin E is the major naturally-occurring "antioxidant" --an antioxidant works against the oxidation process. For this reason, it was thought that vitamin E could possibly have some benefit in preventing atherosclerosis and therefore prevent cardiovascular disease.² Despite the fact that vitamin E can be found in many foods, based on this antioxidant theory, people began to use vitamin E supplements for heart health long before any large clinical studies were performed to test the actual benefit of vitamin E dietary supplements.

What are dietary supplements and why might they be used?

A dietary supplement consists of nutrients people take to provide enough vitamins or minerals that they may not be getting in their regular diet. Many people who use supplements often want to find a cheaper alternative to prescription medications or a more natural way of helping their bodies function. They also may believe that prescription medication is too strong or unsafe. According to one report, about 33% of all adults use at least one supplement and about 50% of all adults older than 55 years of age use at least one supplement.³

Based on the antioxidant theory, some people choose to supplement vitamin E in the form of a tablet or capsule. Vitamin E tablets or capsules can be found in the vitamin section of most drug stores or general nutrition stores. The strengths usually range from 100 international units (IU) to 1000 IU and some people take up to 2000 IU per day. (An IU is a standard for measuring the amount of a substance and is often used with vitamins). Regardless of what vitamin E supplementation is being used for, it is not recommended to take more than 1000 IU per day due to increased risk of side effects. Doses exceeding 400 IU per day should be used with caution. Some of the documented side effects seen in people taking more than 400 IU per day include nausea, vomiting, diarrhea, fatigue, intestinal cramps, weakness, blurred vision, headache, increased bleeding, and rash. Sexual dysfunction and an altered immune system response have been reported in people taking doses over 800 IU.

It is also important to recognize that in the United States, dietary supplements are not approved or regulated by the Food and Drug Administration (FDA). This makes it very hard to know for certain the true benefits or risks of these supplements. Also, there is no way to know if the supplement dosage and amount of the ingredients are the same in each bottle. Therefore, manufacturers of natural products print on each bottle that they do not claim their supplement has the ability to cure or prevent any particular disease. Controversy seems to follow each supplement as to what it does and does not do. Expensive clinical trials are usually not performed; keeping in mind that the supplement manufacturers have no incentive to pay for a clinical trial when they cannot claim that their product treats a disease. This is definitely the case with vitamin E.

Should I use Vitamin E supplementation for cardiovascular protection?

There have been quite a few studies done in the past 10 years that have weighed the benefits and risks of using vitamin E supplements for cardiovascular protection. In the late 1990s and at the turn of the century a lot of the evidence supported the use of vitamin E. But more recently, after larger studies have now been performed, the evidence is changing. Most new studies have found that vitamin E does not really have any cardiovascular protective effect and some studies have found that vitamin E supplementation actually can cause harm.

Recent studies have looked at doses ranging from 136 IU to 800 IU of vitamin E per day. One study found that people taking 800 IU of vitamin E per day experienced a decrease in high-density lipoprotein (HDL) or "good cholesterol" levels. Lower HDL cholesterol puts a person at higher risk for cardiovascular disease. This study also showed that vitamin E minimized the positive effects that prescription cholesterol medication had on HDL cholesterol.⁴

Another recent, large clinical trial looked at 600 IU of vitamin E daily⁵ and another looked at using 600 IU every other day in healthy women⁶. Both trials found that even though vitamin E supplements appeared to be safe, there was no benefit for prevention of cardiovascular disease compared to placebo (a tablet or capsule that looks the same as the drug but does not contain any active drug; placebos are commonly used as a comparison group in studies to determine if a drug has a benefit).

A meta-analysis performed in 2005 found that using vitamin E doses of greater than or equal to 400 IU per day may actually increase death from any cause.⁷ A meta-analysis takes multiple studies that have been performed on one topic and combines the results to see if significant trends can be found. In this case, none of the results from the individual studies were significant, but when the studies were combined, the combined analysis showed an increase in the number of deaths in persons who used vitamin E supplements. The supplement industry disputes this finding because the individuals in these studies were sicker than most people who take vitamin E. Persons in the studies usually were taking other supplements (such as vitamin C and beta-carotene) along with vitamin E. Therefore, the supplement industry argues that the studies do not conclusively show that higher doses of vitamin E supplements will cause an increased risk of death. However, the fact that vitamin E does not provide any benefit based on many large trials and may possibly increase the death rate in some individuals should alert people that it may not be the best dietary supplement to take for heart disease prevention.

When looking at all the evidence available, there is no conclusive benefit for using vitamin E supplementation to prevent cardiovascular disease. While in theory, use of vitamin E as an antioxidant should help prevent LDL cholesterol from building up in the arteries, clinical studies have not shown a clear link between vitamin E supplements and prevention of cardiovascular disease. However, it is always a good idea to make sure enough vitamin E is consumed in the diet to reach the recommended daily value (approximately 22-28 IU per day). At this time, it is more beneficial to focus on a healthy diet and exercise program to prevent cardiovascular disease.

How can vitamin E be supplemented through the diet?

Vitamin E can be supplemented through the diet by eating the right foods. Recommended daily values of vitamin E are 22 International Units (IU) for men and women over 14 years old and 28 IU for women who are breastfeeding. There are many different ways that people can supplement themselves with vitamin E. Wheat germ oil contains the highest amount of vitamin E in a food source and is available in most health food stores.8 Some common foods that are good sources of vitamin E include:

• wheat germ oil (37.2 IU vitamin E per tablespoon)
• soy yogurt (33.0 IU vitamin E per cup)
• sunflower seeds (26.8 IU vitamin E per one-fourth cup)
• mayonnaise (16.5 IU vitamin E per tablespoon)
• almonds (12.7 IU vitamin E per one-fourth cup)
• sunflower oil (12.7 IU vitamin E per tablespoon)
• pecans (12.0 IU vitamin E per one-fourth cup)
• hazelnuts (12.0 IU vitamin E per one-fourth cup)
• margarine (12.0 IU vitamin E per tablespoon)
• sweet potato (9.0 IU vitamin E in one medium potato)
• peanuts (4.9 IU vitamin E per one-fourth cup)
• peanut butter (3.8 IU vitamin E per 2 tablespoons)
• spinach (3.0 IU vitamin E per 2 cups)

If a label expresses the vitamin E level in milligrams (mg), a conversion to International Units is possible: 1 IU vitamin E = 0.67 mg Vitamin E.⁸

For example: A food label lists 20 mg of vitamin E per serving in the product. You can convert this to IUs by taking the number of mg and dividing by 0.67.

In this example: 20 mg divided by 0.67 equals 29.85 IU vitamin E per serving.

Conclusion

So, the bottom line is this--for heart health, it is best to ensure that you are eating a healthy diet (low fat, low cholesterol, and include foods that contain vitamin E in your diet) along with living a healthy lifestyle (exercise, limit alcohol consumption, and avoid smoking). But, at this time, based on recent clinical trials, it is advised to not use vitamin E dietary supplements for heart protection. And, it is always advised to discuss the use of any dietary supplement with your personal health care provider before using the supplement.

References

1. Cardiovascular Disease Statistics. American Heart Assoication. URL: http://www.americanheart.org/presenter.jhtml?dentifier=4478. Accessed April 10, 2008.
2. Vitamin E. Clinical Pharmacology Online. URL: www.clinicalpharmacology-ip.com. Accessed April 9, 2008.
3. Greenberg ER. Vitamin E Supplements: Good in Theory, but Is the Theory Good? Annals of Internal Medicine. 2005; 142:75-76.
4. Brown BG, Zhao XQ, Chait A, et. al. Simvastatin and Niacin, Antioxidant Vitamins, or the Combination for the Prevention of Coronary Disease. The New England Journal of Medicine. 2001;345:1583-1592.
5. Collins R, Armitage J, Parish S, et. al. The Heart Protection Study Collaborative Group. MRC/BHF Heart Protection Study of antioxidant vitamin supplementation in 20,536 high-risk individuals: a randomised placebo-controlled trial. Lancet 2002; 360:23-33.
6. Lee I, Cook NR, Gaziano JM, et. al. Vitamin E in the Primary Prevention of Cardiovascular Disease and Cancer. The Women?s Health Study: A Randomized Controlled Trial. JAMA 2005; 294: 56-65.
7. Miller ER, Pastor-Barriuso R, Dalal D, et. al. Meta-Analysis: High-Dosage Vitamin E Supplementation May Increase All-Cause Mortality. Annals of Internal Medicine. 2005;142:37-46.
8. Nutrition Fact Sheet. Northwestern University. URL: http://www.feinberg.northwestern.edu/nutrition/factsheets/vitamin-e.html. Accessed April 10, 2008.