Soy and Hot Flashes

Written by Dr. Steve Chaney on . Posted in current health articles, Health Current Events, Nutritiion

Will Soy Put Out The Fire?

Author: Dr. Stephen Chaney

 

soy and hot flashesThere has been a lot of controversy in recent years about soy and hot flashes. The question is whether soy isoflavones reduce the hot flashes associated with menopause.

And this is an important question! Because of concerns about increase heart attack risk with hormone replacement therapy (HRT) many women have been looking for natural alternatives to HRT for reducing hot flashes and other symptoms of menopause. They’ve been asking whether soy isoflavones are effective, and the answers that they’ve been getting have been confusing.

For example, you can still find many experts and health professionals who will tell you that soy isoflavones have no proven effect on menopause symptoms.

That is somewhat surprising since two recent meta-analyses (Howes et al, Maturitas, 55: 203-211, 2006; Williamson-Hughes, Menopause, 55: 203-211, 2006) and a 2010 expert panel of The North American Menopause Society have all concluded that soy isoflavones alleviate hot flashes.

Will Soy Put Out The Fire?

However, clear guidance in this area was sorely needed, so Taku et al (Menopause, DOI: soy10.1097/gme.0b013e3182410159, 2012) performed an even larger meta-analysis that included 19 published clinical trials – some of which had been published after the previous two meta-analyses were performed.

I’ve talked about meta-analyses before, so you probably already know that they are very powerful because they combine the results of many individual clinical trials into a single data analysis.

But you also may remember me telling you that meta-analyses can be misleading if they introduce bias because of the kinds of clinical studies that they exclude from their analysis.

So I examined the design of this meta-analysis very carefully. It excluded clinical trials that:

  • were not double blind, placebo controlled and designed in such a manner that the placebo was indistinguishable from the soy isoflavone preparation.
  • contained other substances in addition to the soy isoflavones (The presence of other substances in the preparation might have influenced the response).

There were several other well justified reasons for excluding some studies from the meta-analysis, but they were technical in nature. In my opinion this was a very well designed study.

And the results were clear cut. An average of 54 mg of soy isoflavones (some studies used a little less, some a little more) was sufficient to reduce:

  • the frequency of hot flashes by 21% – and –
  • the severity of hot flashes by 26%

Soy and Hot Flashes: What This Study Mean For You?

The results of this study were highly statistically significant. So if you are suffering from hot flashes and are wondering whether soy isoflavones will put out the fire, the answer appears to be YES.

That’s the good news.

The bad news is that 21-26% is not a huge effect.

And, if you look at the individual clinical studies it is apparent that the response is highly variable. Some women experience major relief from hot flashes and other menopause symptoms, while other women experience little or no relief.

The reason for this variability is not known, but it is likely that the effectiveness of soy isoflavones on reducing hot flashes is modified by other components of the diet and by lifestyle factors such as obesity, exercise and stress.

Soy and hot flashes; the bottom line.

My take on this is that soy isoflavones should not be thought of as a “magic bullet” that will make hot flashes go away by themselves, but rather as a proven part of a holistic approach that encompasses a healthy diet, exercise, weight control and stress reduction

The Bottom Line

  • A recent meta-analysis of 19 published clinical studies showed that soy isoflavones reduced the frequency of hot flashes by 21% and the severity of hot flashes by 26%.
  • The results were highly statistically significant, but 21-26% reduction in symptoms is not a huge effect.
  • When they looked at the individual clinical studies it was apparent that the response is highly variable. Some women experienced major relief from hot flashes and other menopause symptoms, while other women experienced little or no relief.
  • My take on this is that soy isoflavones should not be thought of as a “magic bullet” that will make hot flashes go away by themselves, but rather as a proven part of a holistic approach that encompasses a healthy diet, exercise, weight control and stress reduction

 

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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Latest Article

Does Protein Supplement Timing Matter?

Posted May 15, 2018 by Dr. Steve Chaney

How Do You Gain Muscle Mass & Lose Fat Mass?

Author: Dr. Stephen Chaney

 

protein supplement timingMost of what you read about protein supplements on the internet is wrong. That is because most published studies on protein supplements:

  • Are very small
  • Are not double blinded.
    • Both the subjects and the investigators knew who got the protein supplement.
  • Are done by individual companies with their product.
    • You have no idea which ingredients are in their product are responsible for the effects they report.
    • You have no idea how their product compares with other protein products.
    • There is no standardization with respect to the amount or type of protein or the addition of non-protein ingredients.

Because of these limitations there is a lot of misleading information on the benefits of protein supplements timing and maximal benefit. Let’s start by looking at why people use protein supplements. Let’s also look at what is generally accepted as true with respect to the best supplement timing.

There are 4 major reasons people consume protein supplements:

  • Enhance the muscle gain associated with resistance training: In this case, protein supplements are customarily consumed concurrently with the workout.
  • Preserve muscle and accelerate fat loss while on a weight loss diet: In this case, protein supplements are customarily consumed with meals or as meal replacements.
  • Provide a healthier protein source. In this case, protein supplements are customarily consumed with meals in place of meat protein.
  • Prevent muscle loss associated with aging or illness. There is no customary pattern associated with this use of protein supplements.

How good are the data supporting the customary timing of protein supplementation? The answer is: Not very good. The timing is based on a collection of weak studies which do not always agree with each other.

The current study  (J.L. Hudson et al, Nutrition Reviews, 76: 461-468, 2018 ) was designed to fill this void in our knowledge. It is a meta-analysis that compares all reasonably good studies that have looked at the effect of protein supplement timing on weight gain or loss, lean muscle mass gain, fat loss, and the ratio of lean muscle mass to fat mass.

How Was The Study Done?

The authors started by doing a literature search of all studies that met the following criteria:

  • The study was a randomized control trial with parallel design. This means that study contained a control group. It does not mean that the investigators or subjects were blinded with respect to which subjects used a protein supplement and which did not.
  • The subjects were engaged in resistance training.
  • The study lasted 6 weeks or longer.
  • Reliable methods were used to measure body composition (lean muscle mass and fat mass).
  • The subjects were healthy and at least 19 years old.
  • There was no restriction on the food the subjects consumed.

The authors started with 2074 published studies and ended up with 34 that met all their criteria. They then separated the studies into two groups – those in which the protein supplements were used with meals and those in which the protein supplements were used between meals.

Both groups were diverse.

  • Group 1 included subjects who consumed their protein supplement with their meal and those who consumed their protein supplement as a meal replacement.
  • Group 2 included subjects who consumed their protein supplement concurrent with exercise (usually immediately after exercise) and those who consumed their protein supplement at a fixed time of day not associated with exercise.

Does Protein Supplement Timing Matter?

 

protein supplement timing workoutsBecause the individual studies were very diverse in the way they were designed, the authors could not calculate a reliable estimate of how much lean muscle mass was increased or fat mass was decreased. Instead, they calculated the percentage of studies showing an increase in lean muscle mass or a decrease in fat mass.

When the authors compared protein supplements consumed with meals versus protein supplements consumed between meals:

  • Weight gain was observed in 56% of the studies of protein supplementation with meals compared to 72% of the studies of protein supplementation between meals. In other words, protein supplements consumed with meals were less likely to lead to weight gain than protein supplements consumed between meals.
  • An increase in lean muscle mass was observed in 94% of the studies of protein supplementation with meals compared to 90% of the studies of protein supplementation between meals. In other words, timing of protein supplementation did not matter with respect to increase in muscle mass.
  • A loss of fat mass was observed in 87% of the studies of protein supplementation with meals compared to 59% of the studies of protein supplementation between meals. In other words, protein supplements consumed with meals were more likely to lead to loss of fat mass.
  • An increase in the ratio of lean muscle mass to fat mass was observed in 100% of the studies of protein supplementation with meals compared to 87% of the studies of protein supplementation between meals. In short, protein supplements consumed with meals were slightly more likely to lead to an increase in the ratio of lean muscle mass to fat mass.

The following seem to suggest protein supplement timing matters:

The authors pointed out that their findings were consistent with previous studies showing that when protein supplements are consumed with a meal they displace some of the calories that otherwise would have been consumed. Simply put, people naturally compensate by eating less of other foods.

In contrast, the authors stated that previous studies have shown that when foods, especially liquid foods, are consumed as snacks (between meals), people are less likely to compensate by reducing the calories consumed in the next meal.

The others concluded: “Concurrently with resistance training, consuming protein supplements with meals, rather than between meals, may more effectively promote weight control and reduce fat mass without influencing improvements in lean [muscle] mass.”

What Are The Limitations Of The Study?

Meta-analyses such as this one, are only as good as the studies included in the meta-analysis. Unfortunately, most sports nutrition studies are very weak studies. Thus, this meta-analysis is a perfect example of the “Garbage In: Garbage Out (GI:GO)” phenomenon.

For example, let’s start by looking at what the term “protein supplement” meant.

  • Because the studies were done by individual companies with their product, the protein supplements in this meta-analysis:
    • Included whey, casein, soy, bovine colostrum, rice or combinations of protein sources.
    • Were isolates, concentrates, or hydrolysates.
    • Contained various additions like creatine, amino acids, and carbohydrate.
  • As I discuss in my book, Slaying the Food Myths, previous studies have shown that optimal protein and leucine levels are needed to maximize the increase in muscle mass and decrease in fat mass associated with resistance exercise. However, neither protein nor leucine levels were standardized in the protein supplements included in this meta-analysis.
  • Previous studies have shown that protein supplements that have little effect on blood sugar levels (have a low glycemic index) are more likely to curb appetite. However, glycemic index was not standardized for the protein supplements included in this meta-analysis.

protein supplement timing workout peopleIn short, the conclusions of this study might be true for some protein supplements, but not for others. We have no way of knowing.

We also need to consider the composition of the two groups.

  • Protein supplements used as meal replacements are more likely to decrease weight and fat mass than protein supplements consumed with meals. Yet, both were included in group 1.
  • Some studies suggest that protein supplements consumed concurrent with resistance exercise are more likely to increase muscle mass than protein supplements consumed another time of day. Yet, both are included in group 2. We also have no idea whether the meals with protein supplements in group 1 were consumed shortly after exercise or at an entirely different time of day.

This was the most glaring weakness of the study because it was completely avoidable. The authors could have grouped the studies into categories that made more sense.

In other words, there are multiple weaknesses that limit the predictive power of this study.

What Can We Learn From This Study?

Despite its many limitations, this study does remind us that protein supplements do have calories. This is of relatively little importance for people whose primary goal is to increase lean muscle mass.

However, most of us are using protein supplements to lose weight or to increase our lean mass to fat mass ratio. Simply put, we are either trying to lean out (shape up) or lose weight. And, we want to lose that weight primarily by getting rid of excess fat. For us, calories do matter. With that in mind:

  • If we are consuming a protein supplement immediately after exercise or between meals we probably should make a conscious effort to reduce our daily caloric intake elsewhere in our diet.
  • Alternatively, we could consume the protein supplement with a meal, but time the meal so it occurs shortly after exercise.

 

The Bottom Line:

 

A recent study looked at the optimal timing of protein supplements consumed by subjects who were engaged in resistance exercise. Specifically, the study compared protein supplements consumed with meals versus protein supplements consumed between meals on weight, lean muscle mass, fat mass, and the ratio of lean muscle mass to fat mass. The study reported:

  • Protein supplements consumed with meals were less likely to lead to weight gain than protein supplements consumed between meals.
  • Timing of protein supplementation did not matter with respect to increase in muscle mass.
  • Protein supplements consumed with meals were more likely to lead to loss of fat mass.
  • Protein supplements consumed with meals were slightly more likely to lead to an increase in the ratio of lean mass to fat mass.

The authors pointed out that their findings were consistent with previous studies showing that when a protein supplement was consumed with a meal it displaces some of the calories that would have been otherwise consumed. Simply put, people naturally compensate by eating less of other foods.

In contrast, the authors said that previous studies have shown that when foods, especially liquid foods, are consumed as snacks (between meals), people are less likely to compensate by reducing the calories consumed in the next meal.

As discussed in the article above, the study has major weaknesses. However, despite its many weaknesses, this study does remind us that protein supplements do have calories. This is of relatively little importance for people whose primary goal is to increase lean muscle mass.

However, for those of us who are using protein supplements to lose weight or to increase our lean mass to fat mass ratio, calories do matter.  With that in mind:

  • If we are consuming a protein supplement immediately after exercise or between meals we probably should make a conscious effort to reduce our daily caloric intake elsewhere in our diet.
  • Alternatively, we could consume the protein supplement with a meal, but time the meal so it occurs shortly after exercise.

For more details, read the article above:

 

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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