Do Selenium & Vitamin E Increase Prostate Cancer Risk?

Written by Dr. Steve Chaney on . Posted in Issues, Supplements and Health

Should Men Avoid Those Supplements?

 Author: Dr. Stephen Chaney

Vitamin EYou’ve probably seen the headlines saying “Supplementation with selenium and vitamin E increases the risk of prostate cancer.” The authors of the study even said “Men aged greater than 55 should avoid supplements with either vitamin E or Se (selenium) at doses that exceed recommended dietary intakes.”

In a recent “Health Tips From The Professor” I debunked the headlines saying “Omega-3 fatty acids increase prostate cancer risk“.

What about vitamin E and selenium? Is it true that they increase prostate cancer risk? If you are a man over 55, should you be concerned? Should you stop using supplements containing vitamin E and selenium?

Do Selenium & Vitamin E Increase Prostate Cancer Risk?

Previous Studies On Selenium, Vitamin E And Prostate Cancer Risk

The study that generated the initial excitement in the field was the Nutrition Prevention of Cancer (NPC) Trial that ended in 1998 (Clark et al, British Journal of Urology, 81: 730-734, 1998; Duffield-Lillico et al, British Journal of Urology, 91: 608-612, 2003).

That study showed that supplementing men who had low blood levels of selenium with 200 ug/day of selenium decreased their prostate cancer risk by 65%.

It was followed by a second, much larger trial called the Selenium and Vitamin E Cancer Prevention Trial (SELECT) (Lipmann et al, JAMA, 301: 39-51, 2009). It looked at supplementation with 200 ug/day of selenium and/or 400 IU/day of synthetic alpha-tocopherol.

The SELECT study found no protective effect of either selenium or vitamin E on prostate cancer risk, but did suggest that vitamin E might actually cause a slight increase in prostate cancer risk.

The Study That Generated The Headlines

The authors of the study that generated the recent headlines (Kristal et al, Journal of the National Cancer Institute, doi: 10.1093/jnci/djt456, 2014) were attempting to find a simple explanation for the unexpected results of the SELECT study.

They hypothesized that the baseline selenium status at the beginning of the study might have influenced the outcome of supplementation. Kristal et al reanalyzed the data from the SELECT trial, comparing the effect of selenium and vitamin E supplementation in men with low selenium status and men with high selenium status.

However, at face value their data were confusing rather simplifying. They found:

  • Supplementation with selenium had no effect on prostate cancer risk in men with low selenium status, but increased prostate cancer risk by 91% in men with high selenium status.
  • Conversely, supplementation with 400 IU of vitamin E had no effect on prostate cancer risk in men with high selenium status, but increased prostate cancer risk by 63% in men with low selenium status.

Based on this hodge-podge of data, they concluded that “Men aged greater than 55 should avoid supplements with either vitamin E or Se (selenium) at doses that exceed recommended dietary intakes.” That was the statement that generated the headlines. Was that recommendation justified?

What Do Other Experts Say?

There was an editorial evaluation of the paper by some of the top expects in the field in the same journal (Frankel et al, Journal of the National Cancer Institute, doi: 10.1093/jnci/dju005, 2014) that provided thoughtful explanations of the confusing data in the paper by Kristal et al. They examined three questions:

1)     Why did the SELECT study find no effect of selenium supplementation in men with low selenium status, while the earlier NPC trial found a 65% decrease in prostate cancer risk?

  • The authors of the editorial pointed out that the lowest baseline selenium status in the SELECT trial was much higher than the lowest baseline selenium status in the previous NPC trial. In fact the baseline selenium status in the SELECT trial was at a level in which no effect of selenium supplementation would have been expected based on the results from the NPC trial.

The authors speculated that the addition of selenized yeast to animal feed has improved selenium status in the US population to the point where selenium supplementation can no longer be expected to reduce prostate cancer risk.

2)     Why did selenium supplementation increase prostate cancer risk in men with high selenium status, but not in men with low selenium status?

  • The authors pointed out that for selenium there is a very narrow range between sufficient intake and toxicity. The daily value (DV) for selenium is 90 ug/day and the recommended upper limit (UL) for selenium intake is 400 ug/day.

The average selenium intake for adult men in this country is 151 ug/day. That’s just the average. It’s not hard to imagine that adding 200ug/day of selenium to men at the highest selenium intake could move them into the toxic range.

3)     Why did vitamin E supplementation increase prostate cancer risk in men with low selenium status, but not in men with high selenium status?

  • In part, the authors felt that the pure alpha-tocopherol used in the SELECT trial was not optimal. Pure alpha-tocopherol interferes with the absorption of the other naturally occurring forms of vitamin E, such as gamma-tocopherol – which is the form of vitamin E that decreases prostate cancer risk in animal studies.
  • The authors also noted that vitamin E and selenium work together to inactivate free radicals in cell membranes. Vitamin E reduces the free radicals to a chemically unstable intermediate that still has the potential to damage membranes. A selenium-containing enzyme is required to convert that unstable intermediate into a completely harmless compound.

So when vitamin E is present in much higher levels than selenium, as it was in the group with low baseline selenium status, unstable radicals can accumulate and membrane damage can occur. The authors felt that this was the most likely explanation of the increased prostate cancer risk when men with low selenium status were supplemented with high dose vitamin E.

The authors of the editorial had a much more nuanced interpretation of the data reported by Kristal et al. If you read their evaluation carefully you would likely conclude that you should avoid high dose selenium supplements. However, rather than simply avoiding vitamin E supplements, you should choose vitamin E supplements that contain all of the naturally occurring vitamin E forms and contain near DV amounts of selenium.

These recommendations would be a much better fit to the data, but don’t lend themselves to dramatic headlines – so the editorial has been largely ignored by the press.

The Bottom Line:

1)     Ignore the scary headlines about selenium and vitamin E causing prostate cancer. You can continue to use your supplements as long as you choose ones that are well balanced.

2)     Conversely, if you are at risk of prostate cancer, there is no good evidence that supplementation with either selenium or vitamin E will reduce your risk.

3)     The results of this study are fully consistent with my longstanding recommendation to follow a holistic approach to supplementation and to avoid high dose single nutrient supplements.

4)     There is no reason to supplement with 200 ug/day of selenium. If you are already getting good amounts of selenium from your diet, that dosage could be toxic and may actually increase your risk of cancer. Make sure that your supplements have no more than the DV (70 ug) of selenium.

5)     Avoid high purity alpha-tocopherol supplements. Look for vitamin E supplements containing the full spectrum of tocopherols and tocotrienols in addition to alpha-tocopherol. In addition, make sure that your vitamin E supplement also contains selenium at near DV levels.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

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High Protein Diets and Weight Loss

Posted October 16, 2018 by Dr. Steve Chaney

Do High Protein Diets Reduce Fat And Preserve Muscle?

Author: Dr. Stephen Chaney

Healthy Diet food group, proteins, include meat (chicken or turkAre high protein diets your secret to healthy weight loss? There are lots of diets out there – high fat, low fat, Paleolithic, blood type, exotic juices, magic pills and potions. But recently, high protein diets are getting a lot of press. The word is that they preserve muscle mass and preferentially decrease fat mass.

If high protein diets actually did that, it would be huge because:

  • It’s the fat – not the pounds – that causes most of the health problems.
  • Muscle burns more calories than fat, so preserving muscle mass helps keep your metabolic rate high without dangerous herbs or stimulants – and keeping your metabolic rate high helps prevent both the plateau and yo-yo (weight regain) characteristic of so many diets.
  • When you lose fat and retain muscle you are reshaping your body – and that’s why most people are dieting to begin with.

So let’s look more carefully at the recent study that has been generating all the headlines (Pasiakos et al, The FASEB Journal, 27: 3837-3847, 2013).

The Study Design:

This was a randomized control study with 39 young (21), healthy and fit men and women who were only borderline overweight (BMI = 25). These volunteers were put on a 21 day weight loss program in which calories were reduced by 30% and exercise was increased by 10%. They were divided into 3 groups:

  • One group was assigned a diet containing the RDA for protein (about 14% of calories in this study design).
  • The second group’s diet contained 2X the RDA for protein (28% of calories)
  • The third group’s diet contained 3X the RDA for protein (42% of calories)

In the RDA protein group carbohydrate was 56% of calories, and fat was 30% of calories. In the other two groups the carbohydrate and fat content of the diets was decreased proportionally.

Feet_On_ScaleWhat Did The Study Show?

  • Weight loss (7 pounds in 21 days) was the same on all 3 diets.
  • The high protein (28% and 42%) diets caused almost 2X more fat loss (5 pounds versus 2.8 pounds) than the diet supplying the RDA amount of protein.
  • The high protein (28% and 42%) diets caused 2X less muscle loss (2.1 pounds versus 4.2 pounds) than the diet supplying the RDA amount of protein.
  • In case you didn’t notice, there was no difference in overall results between the 28% (2X the RDA) and 42% (3X the RDA) diets.

Pros And Cons Of The Study:

  • The con is fairly obvious. The participants in this study were all young, healthy and were not seriously overweight. If this were the only study of this type one might seriously question whether the results were applicable to middle aged, overweight coach potatoes. However, there have been several other studies with older, more overweight volunteers that have come to the same conclusion – namely that high protein diets preserve muscle mass and enhance fat loss.
  • The value of this study is that it defines for the first time the upper limit for how much protein is required to preserve muscle mass in a weight loss regimen. 28% of calories is sufficient, and there appear to be no benefit from increasing protein further. I would add the caveat that there are studies suggesting that protein requirements for preserving muscle mass may be greater in adults 50 and older.

The Bottom Line:

1)    Forget the high fat diets, low fat diets, pills and potions. High protein diets (~2X the RDA or 28% of calories) do appear to be the safest, most effective way to preserve muscle mass and enhance fat loss in a weight loss regimen.

2)     That’s not a lot of protein, by the way. The average American consumes almost 2X the RDA for protein on a daily basis. However, it is significantly more protein than the average American consumes when they are trying to lose weight. Salads and carrot sticks are great diet foods, but they don’t contain much protein.

3)     Higher protein intake does not appear to offer any additional benefit – at least in young adults.

4)     Not all high protein diets are created equal. What some people call high protein diets are laden with saturated fats or devoid of carbohydrate. The diet in this study, which is what I recommend, had 43% healthy carbohydrates and 30% healthy fats.

5)    These diets were designed to give 7 pounds of weight loss in 21 days – which is what the experts recommend. There are diets out there promising faster weight loss but they severely restrict calories and/or rely heavily on stimulants, they do not preserve muscle mass, and they often are not safe. In addition they are usually temporary.  I do not recommend them.

6)    This level of protein intake is safe for almost everyone. The major exception would be people with kidney disease, who should always check with their doctor before increasing protein intake. The only other caveat is that protein metabolism creates a lot of nitrogenous waste, so you should drink plenty of water to flush that waste out of your system. But, water is always a good idea.

7)     The high protein diets minimized, but did not completely prevent, muscle loss. Other studies suggest that adding the amino acid leucine to a high protein diet can give 100% retention of muscle mass in a weight loss regimen – but that’s another story for another day.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

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