Vitamins C and E Fall Short in Recent Studies

Vitamins are widely used to treat and prevent various illnesses, including cancer and heart disease. Although evidence is still inconclusive in these areas, recent research has not demonstrated significant benefits.

In the latest study, scientists found that supplementation with vitamins C and E did not affect the risk of developing cancer or heart disease.

This large-scale study involved 14,461 male doctors older than 50 years of age who participated in the Physicians' Health Study II. Participants received 400 international units (IU) of vitamin E or placebo every other day and 500 milligrams of vitamin C or placebo daily. The participants were followed for an average of eight years.

The authors presented their findings at the Seventh Annual American Association for Cancer Research International Conference on Frontiers in Cancer Prevention Research. They found that vitamin C and vitamin E supplementation did not reduce the risk of cancer compared to placebo. According to the authors, vitamin E did not have a significant effect on prostate cancer, and neither vitamin C nor E reduced the risk of cancer overall.

The authors also found that the incidence of heart attack, stroke, congestive heart failure and angina was similar among groups. In addition, vitamin supplementation did not decrease the need for cardiac revascularization, a type of surgery that helps restore blood flow to the heart.

This study comes just weeks after the government halted a major study that was testing the effects of vitamin E and selenium, either taken alone or together, on prostate cancer prevention. An early review of the data from the Selenium and Vitamin E Cancer Prevention Trial (SELECT) showed that the supplements were ineffective and may possibly lead to health risks.

Two trends were observed in the SELECT study: slightly more men who took vitamin E alone developed prostate cancer, and slightly more men who took selenium alone developed type 2 diabetes. However, the results were not statistically significant, meaning they could just be coincidental.

In a related study, scientists found that vitamin C supplementation may decrease the effectiveness of anti-cancer drugs. Researchers at Memorial Sloan-Kettering Cancer Center in New York found that cancer cells treated with vitamin C resisted drug therapy by up to 70 percent. They also found that tumors grew more quickly in mice that received cancer cells pretreated with vitamin C.

For more information about vitamins, please visit Natural Standard's Foods, Herbs & Supplements database.

Comments

[J. Young]

Many people take daily supplements to improve health, and this research is suggesting that vitamins C and E do not have an effect on cancer or heart disease. At least no negative effects were reported; unlike the vitamin E and selenium study on prostate cancer prevention, or the possible link that vitamin C actually decreases the effectiveness of anti-cancer drugs. If more studies continue to show no benefits and worse, detrimental effects of supplemental vitamins, then this could have a huge impact on the supplement industry.

[uwak]

What's the side effect when we eat to much vitamin c and e?

[Anne]

The best way to decrease the risk of cardiovascular disease and many types of cancers is to eat a healthy diet, stay physically active and maintain a healthy weight. Unfortunately, such a prescription is not available in a pill.

[Geoff Hunter]

There is no mention of what type of vitamin E that was used.
If it was alpha-tocopherol "D,L", the synthetic type,
then the research is flawed. "D,L," is only half as active as alpha-tocopherol "D," which is the natural form.
Is the supplement industry taking another bashing because of possible flawed research?

[Greg]

I think this just shows that whatever you put in your body will somehow interact. As we all know, something that is supposed to treat can also have side effects that can be detrimental. I think the same goes for vitamins. Although they may not be as potent as prescription medications, they are still reacting once they are ingested.

[Jason KC]

This story comes in the wake of the SELECT, where we find out that taking vitamin E solo may give a person prostate cancer. This does not contest my apple-a-day theory since there’s no vitamin E in there, just vitamin doctor-away apples. This new study seems to say that there is no health benefit, as opposed to the risk concluded in the SELECT study. I guess I should finally throw away that expired selenium if studies keep coming out in this regard.

[Gimly]

It seems true every day or five that whatever we have exercised as scientific fact is in fact totally or mostly incorrect. It’s great to know the new information, but it sorta makes me doubt the new info along with the old. All we know is that we don’t know.

[h. ariel]

Recent studies of antioxidant supplementation may reveal negative or equivocal results on endpoints, in contrast to earlier studies showing marked benefits, due to the advent of antioxidant-like therapies such as HMGcoA reductase inhibitors and ACE inhibitors. The benefits gained in adding antioxidant vitamins to these therapies may be minimal. New studies should assess the potential benefits of antioxidant vitamin therapy in patients who are not receiving these therapies. Or, current studies results should be re-evaluated to ascertain whether benefits were derived in any patients identified as receiving antioxidant vitamin therapy alone.

[K. Kelley]

Vitamins C and E may not have done well in this study, but both have their place in our diets. Vitamin C is water soluble and vitamin E is oil soluble. Do we know that participants took their vitamin E with meals where other oils were present so its effect could be assimilated? The body is complex, and a high dose of vitamin C or E may be ineffective on some but work for others. Both vitamins are antioxidants, and although they may not have had any effect on the risk of developing heart disease or cancer in this study, they have their place when used in the right combination and under the right circumstances.

[Nicolas]

We need to take a closer look at the study before making any type of conclusion. What type of vitamin E was used? What were the patients’ family histories along with their past medical history? What types of cancers were they monitoring? These are just a few examples of questions that should be addressed before concluding that vitamins E and C do not help prevent cancers.

[Kyle]

Something seems to be off about this study. The results are so conflicting about what is known to be true about vitamins C and E. I would advise to not make any alterations to any patients therapy that includes these vitamins until further studies collect the same results.

[SUMA]

According to an article written by the Linus Pauling Institute, “it is possible that genetic differences may influence the effect of vitamin supplementation on cardiovascular disease. When the results of one randomized controlled trial were reanalyzed based on haptoglobin genotype, antioxidant therapy (1000mg/d vitamin C + 800IU/d vitamin E) was associated with improvement of coronary atherosclerosis in diabetic women with two copies of the haptoglobin 1 gene but worsening of coronary atherosclerosis in those with two copies of the haptoglobin 2 gene.” It is further stated that “the significance of these findings is not entirely clear, but they suggest that there may be a sub-population of people with diabetes who will benefit from antioxidant therapy, while others may not benefit or could actually be harmed.” The article further states that several studies had failed to find significant reductions in the risk of coronary artery disease among vitamin C supplement users in well-nourished populations.

One notable exception was the First National Health and Nutrition Examination Study (NHANES) Epidemiologic Follow-up study. This study found that the risk of death from cardiovascular diseases was 42 percent lower in men and 25 percent lower in women who consumed more than 50mg/day of dietary vitamin C and who regularly took vitamin C supplements, corresponding to a total vitamin C intake of about 300mg/day. Results from the Nurses’ Health Study, based on the follow-up of more than 85,000 women older than 16 years of age, also suggest that higher vitamin C intakes may be cardio protective. These findings reinforce that the study addressed in this blog must be considered in the context of other studies and that further research is needed.

[liz]

I agree with Gimly that different studies come up with different results, ranging from no health effect to negative effects on same subject. Although I wonder if the dose and type of supplementation used in this study resulted in no health benefits, I think there is no better way than getting it from a diet and healthy lifestyle.

[Becca]

This is a little depressing. I am not completely sold that these studies aren’t underestimating the power of these antioxidants. Antioxidants block some of the damage caused by free radicals, which are largely responsible for our aging process and can contribute to many health conditions such as cancer, heart disease and other inflammatory conditions like arthritis. Antioxidants help reduce the damage to the body caused by toxic chemicals and pollutants. The best way to get our antioxidants is through a healthy, well-balanced diet -- not through supplementation.

[gabby adams]

It’s not just about the battle, it’s about the war. Until we see much more negative data on these two, I will continue to take my selenium and vitamin E and pretend to think they’re amazing. Why does selenium always smell like gross B-Vitamins even though they are different? Who even knows what vitamin E does? It seems pretty sketchy. Just because it’s an antioxidant it gets so much "antioxidant press," and I gotta say, let’s all take a deep breath before busting a food-industry and telling people eggs will kill them one year, and then in the future tell them they are healthy. The Internet seems to expedite this, as anytime a blogger presents something controversial, it gets reverbed and amplified as truth. Enough ranting, I’m going to get reading.

[Tricia]

So many people are taking extra vitamin C now that it's cold and flu season, that this study makes me take note -- look at products like Emergen-C® and Airborne® that are flying off the shelves. Should we all be alarmed?

I thought it was particularly impressive that the data for the first study on cancer/heart disease and these vitamins were gathered over eight years.

[kd lisper]

Five cookies in a one hand, seven in the other. These findings do not vary highly and could easily be due to chance. There had to be so many other confounding factors in the lives of these men other than just vitamins. They could have been exposed to carcinogens of unknown proportion over the time. They were properly matched, from what we know, but we do not know very much about this subject. Some chemical whiff from 1977 of any flavor/odor could have easily been an intermediary precursor to destruction down the road.

[ciscount supplements]

I didn't know that supplementation with vitamins C and E did not affect the risk of developing cancer or heart disease. And i agree, this just shows that whatever you put in your body will somehow interact. I enjoyed reading. Thanks for sharing.

[mia]

Before discarding vitamins C and E as ineffective in preventing cancer or heart disease, we need to look at possible confounding variables involved in the study. Many risks and factors can lead to the development of cancer and heart disease. Therefore, these factors must be ruled out before rendering the data as negative for the prevention of these diseases. Based on the pharmacology of vitamins C and E, the results of the study are contradictory.

[RZD]

I've read a lot about vitamin E and its effects from prolonged use to prevent cancer. The findings I came across were similar.

On the other hand, I didn't know that vitamin C was used for cancer prevention. However, in terms of lung cancer, I know that all smokers should take vitamin C because it helps protect the cells in the lining of the bronchi in the lungs and helps maintain adequate levels of vitamin E as well.

[Kate]

Despite the results of this study, I still believe that vitamins C and E have powerful antioxidant effects against cancer cells. This study seems flawed. Participants took 400IU of vitamin E every other day when the recommended DAILY intake is 1,100 IU (for the natural form) and 1,500 IU for the synthetic form. Meaning, they were likely under-dosed. Also, the type of vitamin E (natural vs. synthetic) is important.

Did subjects have other risk factors for cardiac disease that may not have been addressed?? I believe that many important issues were not addressed to be able to draw conclusions from this study. Further, reliable studies must be done before I stop taking these vitamins.

[matt]

I agree with Mia's comment on the statistics of the study. The data need to be closely analyzed for confounding variables. What if the population that they studied were at higher risk for cancer? Were the subjects on other medications or have a history of cancer in the family? These results wouldn't keep me from taking these vitamins because I feel the benefit outweighs the risks, and the conclusion should always be questioned.

[Luce]

Before we make statements that vitamins E and C are not effective in preventing cardiovascular events, we need to carefully evaluate the study. From my perspective the subjects that are reported in the study might not be the ideal representation of the patients that could benefit from additional supplementation with vitamins E and C. The majority of them had no history of a heart disease (high blood pressure or congestive heart failure) or high cholesterol, which we all can agree are risk factors to a major cardiovascular event like a myocardial infarction (heart attack). We also need to take into consideration their family history of cardiovascular events and their lifestyle choices. Generally, these subjects are healthy and might just need to continue doing what they are doing to stay healthy. On the other hand, patients who might have had an episode of a myocardial infarction or more than one risk factor (high blood pressure, high cholesterol, parental family history of a cardiovascular event, history of diabetes and/or sedentary lifestyle) might be the candidates for extra vitamin supplementation.

However, to the best of my knowledge, I have not seen or heard of any study that has set out to investigate the effects in such a patient population. More research needs to be done, and higher-risk patients should be included and maybe compared to a lower-risk patient population as well.

[Justin]

Like many other antioxidants that are effective against cancer, I still believe that vitamins C and E have powerful antioxidant effects against cancer cells. It’s also important to note that there are two forms of vitamin E: the natural vs. the synthetic form, and both may have different effects. Also, was the dosage regimen appropriate? I personally would not draw conclusions from this study because more reliable studies are needed in this area.

[Diane]

Generally, the study participants are healthy and might not be the ones who benefit from supplementation with vitamins C and E for the prevention of heart disease. Both vitamins C and E are antioxidants. Vitamin C is a water-soluble vitamin, and vitamin E is a fat-soluble vitamin. These vitamins, if used appropriately by the right candidate in the right amount, will definitely provide some benefits. Thus, the fact that this study does not conclude in favor of the vitamins does not imply they can no longer by valued vitamins. They are and will always be. The research probably was not well designed for heart disease. Maybe it could favor another disease state.

[Chris]

In recent years, the vitamin industry has undoubtedly skyrocketed in popularity for just about every ailment there is. I always learned and understood that vitamins are really the most beneficial when you are deficient in them to begin with -- that supplementing many extra pills won't really help cure anything. For instance, for water-soluble vitamins like vitamin C, your body can only absorb so much, so is there really a point in taking more than that amount?

[RN]

Why were they dosing vitamin E every other day? I'm not always a big proponent of taking multitudes of vitamins and supplements, but honestly this trial is really bad because they are not dosing correctly, nor do they have the frequency right. We really need a well-laid-out trial that can give us some hard data.

[MHD]

It is difficult for the general public to assess the importance of vitamins when there are so many conflicting studies. Many studies have claimed that vitamin-C rich foods have significant protective effects against the development of atherosclerosis and cancer. Vitamin C's role as a powerful water-soluble antioxidant minimizes the lipid oxidation that causes atherosclerotic build up. Although previous studies have also suggested that there is no effect from vitamin E, the conflicting information about vitamin C might suggest that more research needs to be done to find a consensus among scientists.