Does Vitamin D Help Prevent Asthma Attacks?

Written by Dr. Steve Chaney on . Posted in Prevent Asthma Attacks, Vitamin D, Vitamins and Health

Author: Dr. Stephen Chaney

breaking newsWhat do the experts say about vitamin D helping to prevent asthma attacks?  You’ve seen the headlines. Vitamin D is no longer just for healthy bones. It has become the latest “miracle” nutrient. If you believe everything you read, vitamin D can prevent or cure everything from multiple sclerosis to diabetes, heart disease, and cancer. Unfortunately, the evidence for many of those claims is weak.

However, the effect of vitamin D on the severity of asthma symptoms appears to be an exception. That relationship appears to be on much more solid ground.

A review published last year(S.K. Bantz et al, Annals of Pediatrics and Child Health, 3: pii: 1032, 2015) concluded “We emphasize that all children, especially those who are asthmatic, should be assessed to ensure adequate intake or supplementation with at least the minimum recommended doses of vitamin D. The simple intervention of vitamin D supplementation may provide significant clinical improvement in atopic disease, especially asthma.” [Note: Atopic disease refers to diseases characterized by a hyperallergenic response, such as eczema, hay fever, and asthma.]

That was followed by the recent publication of a Cochrane Review  that concluded “Vitamin D is likely to offer protection against severe asthma attacks”. To understand the significance of that statement you need to understand that this is not just another clinical study or another review. Cochrane Reviews are conducted by an international group of experts and are considered the “Gold Standard” for evidence-based medicine.

You may remember that famous commercial: “When E.F. Hutton speaks, people listen.”  In this case: “When Cochrane Reviews speak, doctors listen.”

Let’s look briefly at how the review was conducted, and then examine exactly what the review said, and what it didn’t say.

Does Vitamin D Help Prevent Asthma Attacks?

certifiedOne of the characteristics of Cochrane Reviews that set them apart from many of the other reviews that you find in the literature is that they include only the highest quality clinical studies in their analysis. This is one of the things that gives them such credibility.

This particular Cochrane Review included seven trials involving a total of 435 children and two trials involving a total of 658 adults. Most trial participants had mild to moderate asthma. The duration of the trials ranged from four to 12 months.  All studies were placebo controlled and used close to RDA recommended doses of vitamin D.

The results were pretty clear cut:

  • Vitamin D supplementation reduced the average number of severe asthma attacks requiring treatment with oral steroids by 36%.  This conclusion was based on 3 high-quality studies involving 680 participants.  Here, these studies clearly show vitamin D does  help prevent asthma attacks.
  • Vitamin D supplementation reduced the number of acute asthma attacks requiring emergency room visits and/or hospitalizations by 50%. This conclusion was based on 7 high-quality studies with 963 participants.  These studies also show vitamin D helps prevent asthma attacks.
  • None of the studies reported any severe adverse effects from vitamin D supplementation. (Compare that with all warnings associated with those ads for asthma medications you see on TV.)

However, they did not see any effect of vitamin D supplementation on day-to-day asthma symptoms.

What Does This Study Mean For You?

prevent asthmaThis study strongly suggests that vitamin D supplementation in the RDA range (600 IU for ages 1-70 and 800 IU for adults over 70) significantly reduces the risk of severe asthma attacks requiring steroids or hospitalization. Thus, if you or your child have asthma, vitamin D supplementation in the RDA range just makes sense.

However, this study also suggest that vitamin D is not a panacea that will make all asthma symptoms disappear.

Also, even Cochrane Reviews have limitations.

  • None of the studies included in this review looked at vitamin D status prior to the study. We simply don’t know whether vitamin D supplementation might be effective at reducing day-to-day asthma symptoms in individuals who were vitamin D deficient.
  • The studies included in this review did not include asthma sufferers with severe symptoms. Again, we don’t know whether vitamin D supplementation might make day-to-day symptoms more tolerable and easily controlled for people with severe asthma symptoms

One final thought: Blood levels of 25-hydroxy-vitamin D are the best indicators of vitamin D status. For reasons that we don’t understand, not everyone consuming RDA levels of vitamin D ends up with optimal levels (50-75 nmoles/L).  For that reason, it is a good idea to get your blood levels of 25-hydroxy-vitamin D tested as part of your annual physical exam.

If you are already getting RDA levels of vitamin D and your 25-hydroxy-vitamin D levels are not in the optimal range, you may want to supplement with extra vitamin D.  Just be sure to monitor your 25-hydroxy-vitamin D levels on a regular basis to make sure they don’t exceed the optimal range.

So, according to the Cochrane Review, vitamin D does help prevent asthma attacks.

 

The Bottom Line

 

  • A recent Cochrane Review concluded that vitamin D supplementation in the RDA range (600 IU for ages 1-70 and 800 IU for adults over 70) significantly reduces the risk of severe asthma attacks requiring steroids or hospitalization in both children and adults. This is significant because Cochrane Reviews are considered the Gold Standard for evidence-based medicine.
  • Thus, if you or your child have asthma, vitamin D supplementation in the RDA range just makes sense.
  • However, blood levels of 25-hydroxy-vitamin D are the best measure of vitamin status, and not everyone consuming RDA levels of vitamin D ends up with optimal levels (50-75 nmoles/L). If you are already getting RDA levels of vitamin D in your diet and your 25-hydroxy-vitamin D levels are not in the optimal range, you may want to supplement with extra vitamin D. Just be sure to monitor your 25-hydroxy-vitamin D levels on a regular basis to make sure they don’t exceed the optimal range.
  • This Cochrane Review did not find any effect of vitamin D supplementation on day-to-day asthma symptoms.
  • However, even Cochrane Reviews have limitations.
  • None of the studies included in this review looked at vitamin D status prior to the study. We simply don’t know whether vitamin D supplementation might be effective at reducing day-to-day asthma symptoms in individuals who were vitamin D deficient.
  • The studies included in this review did not include asthma sufferers with severe symptoms. Again, we don’t know whether vitamin D supplementation might make day-to-day symptoms more tolerable and easily controlled for people with severe asthma symptoms

 

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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