Magnesium Supplements Benefits | Reduce Diabetes Risk?

Written by Dr. Steve Chaney on . Posted in current health articles, Food and Health, Supplements and Health

Author: Dr. Stephen Chaney

 

reduce diabetes riskI came across an article the other day suggesting that one of the magnesium supplements benefits might be  improved blood sugar control in pre-diabetics with low blood levels of magnesium (Guerrero-Romero et al, Diabetes & Metabolism, 41: 202-207, 2015). Considering that…

  • A 2014 CDC report stated that 1/3 of adult Americans are pre-diabetic, and…
  • Most people with pre-diabetes will go on to develop type 2 diabetes in 10 years or less, and…
  • Diabetes is the 7th leading cause of death in this country, and…
  • 60% of Americans don’t get enough magnesium in their diets…

…this could be a really big deal! Because of this I scrutinized the paper very carefully and reviewed the literature on magnesium intake and the incidence of type 2 diabetes.

 

Do Magnesium Supplements Improve Blood Sugar Control?

This was a relatively small study (116 adults, age 30-65), but it was well designed. All of the subjects had mild impairments in blood sugar control (i.e. were pre-diabetic), and all of them had low blood magnesium levels (≤1.8 mg/dL). This is a significant improvement over most previous studies of magnesium supplementation and blood sugar control because blood magnesium levels were not determined in many of those studies.

magnesium supplements benefitsThe study was double-blind, placebo controlled.Subjects received either 382 mg of magnesium or a placebo each day for 16 weeks, at which time blood sugar control and blood magnesium levels were re-measured. All subjects were put on a weight maintenance diet consisting of 55% healthy carbohydrates, 25% healthy fats, and 20% healthy proteins and told to exercise for at least 30 minutes three times per week.

Adherence to the diet and exercise regimen was 91% in both the supplement and placebo groups. Adherence to magnesium supplementation was 85% as measured by an increase in blood magnesium levels.

At the end of 16 weeks:

  • Improvement in blood sugar control was observed in 50% of the people in the magnesium group compared to 7% in the placebo group. This was significantly different.
  • Triglyceride levels were significantly decreased while HDL and blood magnesium levels were significantly increased in the magnesium group compared to the placebo group.
  • Side effects of magnesium supplementation were mild abdominal pain (7.6%) and diarrhea (6.0%).

The authors concluded:

  • “Our present results demonstrate the efficacy and safety of magnesium supplementation in the reduction of plasma glucose levels and in the improvement of glycemic status [blood sugar control] of pre-diabetic individuals who have low serum magnesium levels.”
  • “Our results support the hypothesis that, as a complement to lifestyle intervention programs, people with pre-diabetes and low blood levels of magnesium also should take magnesium supplements to decrease plasma glucose levels and potentially decrease the transition rate from pre-diabetes to diabetes.”

Magnesium and Blood Sugar Control

reduce blood sugarWhile the results of the recent study were impressive, it was a single, relatively small study, so I did a thorough review of the literature to put this study in perspective. This is what I found:

  • A major study that followed 2,582 participants enrolled in the Framingham Heart Study for 7 years (Hruby et al., Diabetes Care, 37: 419-427, 2014) concluded that those who consumed the most magnesium (400 mg/day) had a 50% reduction in the risk of developing type 2 diabetes compared to those who consumed the least (240 mg/day).

Several other studies comparing magnesium intake to diabetes risk have come to similar conclusions.

  • A meta-analysis of 13 studies with 536,318 people (Dong et al, Diabetes Care, 34: 2116-2122, 2011) concluded that the risk of diabetes was decreased by 14% for every 100 mg of magnesium consumed.
  • Most, but not all, intervention studies like the one described above have shown that magnesium supplementation reduced blood glucose levels and improved blood sugar control.

However, most of these studies did not measure blood magnesium levels. This is a significant drawback because if the majority of subjects in a particular study had adequate blood magnesium levels at the beginning of the study, one would not expect additional magnesium to improve blood sugar control.

  • A study of 4257 participants in the 1999-2000 National Health and Nutrition Examination Survey (Ford &Mokdad, Journal of Nutrition, 133: 2879-2882, 2003) concluded that around 60% of the adult US population was getting sub-optimal levels of magnesium from their diet.

The RDAs for magnesium range from 310-420 mg/day depending on age and gender, while intakes of magnesium ranged from 144-326 mg/day depending on age, gender and ethnicity. Those taking supplements had significantly greater magnesium intake than non-supplement users.

However, dietary recall studies almost always overestimate the percentage of the population that is deficient in any particular nutrient. Blood nutrient levels are usually considered a better indicator of nutrient deficiency, and some experts estimate that 20-30% of the US population may have blood levels of magnesium that are less than optimal.

Unfortunately, in the case of magnesium it is unclear whether even blood levels are an adequate indicator of nutrient status. That’s because only 1% of your body’s magnesium is found in the blood. The rest is locked up in your tissues where it is much more difficult to determine whether your magnesium status is adequate or not.

 

The Bottom Line

  • A recent study showed that magnesium supplementation improves blood sugar control in pre-diabetics with low blood magnesium levels. The authors concluded that magnesium supplementation along with lifestyle change may be effective in slowing the progression from pre-diabetes to type 2 diabetes.
  • This study is consistent with a number of previous studies suggesting that increased magnesium intake is associated with decreased risk of developing type 2 diabetes.
  • This study is also consistent with the principle that supplementation works best in situations where there is a demonstrated need for a particular nutrient, in this case magnesium (the study participants were selected in part on the basis of low blood levels of magnesium).
  • Other studies have shown that around 60% of the population is getting inadequate magnesium from their diet.Dietary recall studies probably overestimate the percentage of the population that is magnesium deficient, but most experts agree that a significant percentage of the US population likely have less than optimal magnesium status.
  • You probably don’t need mega-doses of magnesium to support good blood sugar control. The clinical study described above used 382 mg/day of magnesium, but most dietary recall studies suggest that dietary intake of magnesium in this country is only 100-200 mg/day below RDA recommendations.
  • Assuring an adequate intake of magnesium is only one component of a holistic approach for reducing the risk of developing type 2 diabetes. Other important components are weight control, exercise, and a healthy diet that restricts sugars and starches.
  • Good dietary sources of magnesium include leafy green vegetables (5-6 servings = RDA), nuts (5-6 servings = RDA), orwhole wheat bread or brown rice (8-9 servings = RDA).
  • Supplementation with ≥300 mg of magnesium can cause gas, bloating and diarrhea in sensitive individuals. If you are supplementing with magnesium, I recommend a sustained release supplement.

 

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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Comments (4)

  • MJ Lucas

    |

    Great info to share Dr. Cheney.

    MJ

    Reply

  • Bill Dunstan

    |

    The results of the study do not indicate the bio absorption of the supplementation that was given the participants over the eight year period. And did they compare different companies prior to the initiation of the study for the best bio absorbency of their supplements?

    Reply

    • Dr. Steve Chaney

      |

      Dear Bill,

      Magnesium salts are very soluble in water, so their bioavailability is generally high and relatively independent of the type of magnesium salt used in the supplement. Your question would be much more pertinent to calcium supplements.

      Dr. Chaney

      Reply

  • Carol Pontius

    |

    Very interesting….. as usual!! Thanks for ALL your good information!

    Reply

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Latest Article

Should We Use Supplements For Cardiovascular Health?

Posted July 10, 2018 by Dr. Steve Chaney

Are You Just Wasting Your Money On Supplements?

Author: Dr. Stephen Chaney

 

supplements for cardiovascular health wast moneyYou’ve seen the headlines. “Recent Study Finds Vitamin and Mineral Supplements Don’t Lower Heart Disease Risk.”  You are being told that supplements are of no benefit to you. They are a waste of money. You should follow a healthy diet instead. Is all of this true?

If I were like most bloggers, I would give you a simple yes or no answer that would be only partially correct. Instead, I am going to put the study behind these headlines into perspective. I am going to give you a deeper understanding of supplementation, so you can make better choices for your health.

 Should we use supplements for cardiovascular health?

In today’s article I will give you a brief overview of the subject. Here are the topics I will cover today:

  • Is this fake news?
  • Did the study ask the right questions?
  • Is this a question of “Garbage In – Garbage Out?
  • Reducing Heart Disease Risk. What you need to know.

All these topics are covered in much more detail (with references) in my book “Slaying The Supplement Myths”, which will be published this fall.

 

How Was This Study Done?

supplements for cardiovascular healthThis study (D.J.A. Jenkins et al, Journal of the American College Of Cardiology, 71: 2540-2584, 2018 ) was a meta-analysis. Simply put, that means the authors combined the results of many previous studies into a single database to increase the statistical power of their conclusions. This study included 127 randomized control trials published between 2012 and December 2017. These were all studies that included supplementation and looked at cardiovascular end points, cancer end points or overall mortality.

Before looking at the results, it is instructive to look at the strengths and weaknesses of the study. Rather than giving you my interpretation, let me summarize what the authors said about strengths and weaknesses of their own study.

The strengths are obvious. Randomized control trials are considered the gold standard of evidence-based medicine, but they have their weaknesses. Here is what the authors said about the limitations of their study:

  • “Randomized control trials are of shorter duration, whereas longer duration studies might be required to fully capture chronic disease risk.”
  • “Dose-response data were not usually available [from the randomized control studies included in their analysis]. However, larger studies would allow the effect of dose to be assessed.”

There are some other limitations of this study, which I will point out below.

Is This Fake News?

supplements for cardiovascular health fake newsWhen I talk about “fake news” I am referring to the headlines, not to the study behind the headlines. The headlines were definitive: “Vitamin and Mineral Supplements Don’t Lower Heart Disease Risk.” However, when you read the study the reality is quite different:

  • In contrast to the negative headlines, the study reported:
    • Folic acid supplementation decreased stroke risk by 20% and overall heart disease risk by 17%.
    • B complex supplements containing folic acid, B6, and B12 decreased stroke risk by 10%.
    • That’s a big deal, but somehow the headlines forgot to mention it.
  • The supplements that had no significant effect on heart disease risk (multivitamins, vitamin D, calcium, and vitamin C) were ones that would not be expected to lower heart disease risk. There was little evidence from previous studies of decreased risk. Furthermore, there is no plausible mechanism for supposing they might decrease heart disease risk.
  • The study did not include vitamin E or omega-3 supplements, which are the ones most likely to prove effective in decreasing heart disease risk when the studies are done properly (see below).

Did The Study Ask The Right Question?

Most of the studies included in this meta-analysis were asking whether a supplement decreased heart disease risk or mortality for everyone. Simply put, the studies started with a group of generally healthy Americans and asked whether supplementation had a significant effect on disease risk for everyone in that population.

That is the wrong question. We should not expect supplementation to benefit everyone equally. Instead, we should be asking who is most likely to benefit from supplementation and design our clinical studies to test whether those people benefit from supplementation.

supplements for cardiovascular health diagramI have created the graphic on the right as a guide to help answer the question of “Who is most likely to benefit from supplementation?”. Let me summarize each of the points using folic acid as the example.

 

Poor Diet: It only makes sense that those people who are deficient in folate from foods are the most likely to benefit from folic acid supplementation. Think about it for a minute. Would you really expect people who are already getting plenty of folate from their diet to obtain additional benefits from folic acid supplementation?

The NIH estimates that around 20% of US women of childbearing age are deficient in folic acid. For other segments of our population, dietary folate insufficiency ranges from 5-10%. Yet, most studies of folic acid supplementation lump everyone together – even though 80-95% of the US population is already getting enough folate through foods, food fortification, and supplementation. It is no wonder most studies fail to find a beneficial effect of folic acid supplementation.

The authors of the meta-analysis I discussed above said that the beneficial effects of folic acid they saw might have been influenced by a very large Chinese study, because a much higher percentage of Chinese are deficient in folic acid. They went on to say that the Chinese study needed to be repeated in this country.

In fact, the US study has already been done. A large study called “The Heart Outcomes Prevention Evaluation (HOPE)” study reported that folic acid supplementation did not reduce heart disease risk in the whole population. However, when the study focused on the subgroup of subjects who were folate-deficient at the beginning of the study, folic acid supplementation significantly decreased their risk of heart attack and cardiovascular death.  This would seem to suggest using supplements for cardiovascular health is a good idea.

Increased Need: There are many factors that increase the need for certain nutrients. However, for the sake of simplicity, let’s only focus on medications. Medications that interfere with folic acid metabolism include anticonvulsants, metformin (used to treat diabetes), methotrexate and sulfasalazine (used to treat severe inflammation), birth control pills, and some diuretics. Use of these medications is not a concern when the diet is adequate. However, when you combine medication use with a folate-deficient diet, health risks are increased and supplementation with folic acid is more likely to be beneficial.

Genetic Predisposition: The best known genetic defect affecting folic acid metabolism is MTHFR. MTHFR deficiency does not mean you have a specific need for methylfolate. However, it does increase your need for folic acid. Again, this is not a concern when the diet is adequate. However, when you combine MTHFR deficiency with a folate-deficient diet, health risks are increased and supplementation with folic acid is more likely to be beneficial. I cover this topic in great detail in my upcoming book, “Slaying The Supplement Myths”. In the meantime, you might wish to view my video, “The Truth About Methyl Folate.”

Diseases: An underlying disease or predisposition to disease often increases the need for one or more nutrients that help reduce disease risk. The best examples of this are two major studies on the effect of vitamin E on heart disease risk in women. Both studies found no effect of vitamin E on heart disease risk in the whole population. However, one study reported that vitamin E reduced heart disease risk in the subgroup of women who were post-menopausal (when the risk of heart disease skyrockets). The other study found that vitamin E reduced heart attack risk in the subgroup of women who had pre-existing heart disease at the beginning of the study.

Finally, if you look at the diagram closely, you will notice a red circle in the middle. When two or three of these factors overlap, that is the “sweet spot” where supplementation is almost certain to make a difference and it may be a good idea to use supplements for cardiovascular health.

Is This A Question Of “Garbage In, Garbage Out”?

supplements for cardiovascular health garbage in outUnfortunately, most clinical studies focus on the “Does everyone benefit from supplementation question?” rather than the “Who benefits from supplementation?” question.

In addition, most clinical studies of supplementation are based on the drug model. They are studying supplementation with a single vitamin or mineral, as if it were a drug. That’s unfortunate, because vitamins and minerals work together synergistically. What we need are more studies of holistic supplementation approaches.

Until these two things change, most supplement studies are doomed to failure. They are doomed to give negative results. In addition, meta-analyses based on these faulty supplement studies will fall victim to what computer programmers refer to as “Garbage In, Garbage Out”. If the data going into the analysis is faulty, the data coming out of the study will be equally faulty. It won’t be worth the paper it is written on. If you are looking for personal guidance on supplementation, this study falls into that category.

 

Should We Use Supplements For Cardiovascular Health?

 

If you want to know whether supplements decrease heart disease risk for everyone, this meta-analysis is clear. Folic acid may decrease the risk of stroke and heart disease. A B complex supplement may decrease the risk of stroke. All the other supplements they included in their analysis did not decrease heart disease risk, but the analysis did not include vitamin E and/or omega-3s.

However, if you want to know whether supplements decrease heart disease risk for you, this study provides no guidance. It did not ask the right questions.

I would be remiss, however, if I failed to point out that we know healthy diets can decrease heart disease risk. In the words of the authors: “The recent science-based report of the U.S. Dietary Guidelines Advisory Committee, also concerned with [heart disease] risk reduction, recommended 3 dietary patterns: 1) a healthy American diet low in saturated fat, trans fat, and meat, but high in fruits and vegetables; 2) a Mediterranean diet; and 3) a vegetarian diet. These diets, with their accompanying recommendations, continue the move towards more plant-based diets…” I cover the effect of diet on heart disease risk in detail in my book, “Slaying The Food Myths”.

 

The Bottom Line

 

You have probably seen the recent headlines proclaiming: “Vitamin and Mineral Supplements Don’t Lower Heart Disease Risk.” The study behind the headlines was a meta-analysis of 127 randomized control trials looking at the effect of supplementation on heart disease risk and mortality.

  • The headlines qualify as “fake news” because:
    • The study found that folic acid decreased stroke and heart disease risk, and B vitamins decreased stroke risk. Somehow the headlines forgot to mention that.
    • The study found that multivitamins, vitamin D, calcium, and vitamin C had no effect on heart disease risk. These are nutrients that were unlikely to decrease heart disease risk to begin with.
    • The study did not include vitamin E and omega-3s. These are nutrients that are likely to decrease heart disease risk when the studies are done properly.
  • The authors of the study stated that a major weakness of their study was that that randomized control studies included in their analysis were short term, whereas longer duration studies might be required to fully capture chronic disease risk.
  • The study behind the headlines is of little use for you as an individual because it asked the wrong question.
  • Most clinical studies focus on the “Does everyone benefit from supplementation question?” That is the wrong question. Instead we need more clinical studies focused on the “Who benefits from supplementation?” question. I discuss that question in more detail in the article above.
  • In addition, most clinical studies of supplementation are based on the drug model. They are studying supplementation with a single vitamin or mineral, as if it were a drug. That’s unfortunate, because vitamins and minerals work together synergistically. What we need are more studies of holistic supplementation approaches.
  • Until these two things change, most supplement studies are doomed to failure. They are doomed to give negative results. In addition, meta-analyses based on these faulty supplement studies will fall victim to what computer programmers refer to as “Garbage In, Garbage Out”. If the data going into the analysis is faulty, the data coming out of the study will be equally faulty. It won’t be worth the paper it is written on. If you are looking for personal guidance on supplementation, this study falls into that category.
  • If you want to know whether supplements decrease heart disease risk for everyone, this study is clear. Folic acid may decrease the risk of stroke and heart disease. A B-complex supplement may decrease the risk of stroke. All the other supplements they included in their analysis did not decrease heart disease risk, but they did not include vitamin E and/or omega-3s in their analysis.
  • If you want to know whether supplements decrease heart disease risk for you, this study provides no guidance. It did not ask the right questions.
  • However, we do know that healthy, plant-based diets can decrease heart disease risk. I cover heart healthy diets in detail in my book, “Slaying The Food Myths.”

 

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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