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

A Low Carb Diet and Weight Loss

Posted January 15, 2019 by Dr. Steve Chaney

Do Low-Carb Diets Help Maintain Weight Loss?

Author: Dr. Stephen Chaney

 

low carb dietTraditional diets have been based on counting calories, but are all calories equal? Low-carb enthusiasts have long claimed that diets high in sugar and refined carbs cause obesity. Their hypothesis is based on the fact that high blood sugar levels cause a spike in insulin levels, and insulin promotes fat storage.

The problem is that there has been scant evidence to support that hypothesis. In fact, a recent meta-analysis of 32 published clinical studies (KD Hall and J Guo, Gastroenterology, 152: 1718-1727, 2017 ) concluded that low-fat diets resulted in a higher metabolic rate and greater fat loss than isocaloric low-carbohydrate diets.

However, low-carb enthusiasts persisted. They argued that the studies included in the meta-analysis were too short to adequately measure the metabolic effects of a low-carb diet. Recently, a study has been published in the British Medical Journal (CB Ebbeling et al, BMJ 2018, 363:k4583 ) that appears to vindicate their position.

Are low carb diets best for long term weight loss?

Low-carb enthusiasts claim the study conclusively shows that low-carb diets are best for losing weight and for keeping it off once you have lost it. They are saying that it is time to shift away from counting calories and from promoting low-fat diets and focus on low-carb diets instead if we wish to solve the obesity epidemic. In this article I will focus on three issues:

  • How good was the study?
  • What were its limitations?
  • Are the claims justified?

 

How Was The Study Designed?

low carb diet studyThe investigators started with 234 overweight adults (30% male, 78% white, average age 40, BMI 32) recruited from the campus of Framingham State University in Massachusetts. All participants were put on a diet that restricted calories to 60% of estimated needs for 10 weeks. The diet consisted of 45% of calories from carbohydrate, 30% from fat, and 25% from protein. [So much for the claim that the study showed low-carb diets were more effective for weight loss. The diet used for the weight loss portion of the diet was not low-carb.]

During the initial phase of the study 161 of the participants achieved 10% weight loss. These participants were randomly divided into 3 groups for the weight maintenance phase of the study.

  • The diet composition of the high-carb group was 60% carbohydrate, 20% fat, and 20% protein.
  • The diet composition of the moderate-carb group was 40% carbohydrate, 40% fat, and 20% protein.
  • The diet composition of the low-carb group was 20% carbohydrate, 60% fat, and 20% protein.

Other important characteristics of the study were:

  • The weight maintenance portion of the study lasted 5 months – much longer than any previous study.
  • All meals were designed by dietitians and prepared by a commercial food service. The meals were either served in a cafeteria or packaged to be taken home by the participants.
  • The caloric content of the meals was individually adjusted on a weekly basis so that weight was kept within a ± 4-pound range during the 5-month maintenance phase.
  • Sugar, saturated fat, and sodium were limited and kept relatively constant among the 3 diets.

120 participants made it through the 5-month maintenance phase.

 

Do Low-Carb Diets Help Maintain Weight Loss?

low carb diet maintain weight lossThe results were striking:

  • The low-carb group burned an additional 278 calories/day compared to the high-carb group and 131 calories/day more than the moderate-carbohydrate group.
  • These differences were even higher for those individuals with higher insulin secretion at the beginning of the maintenance phase of the study.
  • These differences lead the authors to hypothesize that low-carb diets might be more effective for weight maintenance than other diets.

 

What Are The Pros And Cons Of This Study?

low carb diet pros and consThis was a very well-done study. In fact, it is the most ambitious and well-controlled study of its kind. However, like any other clinical study, it has its limitations. It also needs to be repeated.

The pros of the study are obvious. It was a long study and the dietary intake of the participants was tightly controlled.

As for cons, here are the three limitations of the study listed by the authors:

#1: Potential Measurement Error: This section of the paper was a highly technical consideration of the method used to measure energy expenditure. Suffice it to say that the method they used to measure calories burned per day may overestimate calories burned in the low-carb group. That, of course, would invalidate the major findings of the study. It is unlikely, but it is why the study needs to be repeated using a different measure of energy expenditure.

#2: Compliance: Although the participants were provided with all their meals, there was no way of being sure they ate them. There was also no way of knowing whether they may have eaten other foods in addition to the food they were provided. Again, this is unlikely, but cannot be eliminated from consideration.

#3: Generalizability: This is simply an acknowledgement that the greatest strength of this study is also its greatest weakness. The authors acknowledged that their study was conducted in such a tightly controlled manner it is difficult to translate their findings to the real world. For example:

  • Sugar and saturated fat were restricted and were at very similar levels in all 3 diets. In the real world, people consuming a high-carb diet are likely to consume more sugar than people in the other diet groups. Similarly, people consuming the low-carb diet are likely to consume more saturated fat than people in the other diet groups.
  • Weight was kept constant in the weight maintenance phase by constantly adjusting caloric intake. Unfortunately, this seldom happens in the real world. Most people gain weight once they go off their diet – and this is just as true with low-carb diets as with other diets.
  • The participants had access to dietitian-designed prepared meals 3 times a day for 5 months. This almost never happens in the real world. The authors said “…these results [their data] must be reconciled with the long-term weight loss trials relying on nutrition education and behavioral counseling that find only a small advantage for low carbohydrate compared with low fat diets according to several recent meta-analyses.” [I would add that in the real world, people do not even have access to nutritional education and behavioral modification.]

 

low carb diet and youWhat Does This Study Mean For You?

  • This study shows that under very tightly controlled conditions (dietitian-prepared meals, sugar and saturated fat limited to healthy levels, calories continually adjusted so that weight remains constant) a low-carb diet burns more calories per day than a moderate-carb or high-carb diet. These findings show that it is theoretically possible to increase your metabolic weight and successfully maintain a healthy weight on a low-carb diet. These are the headlines you probably saw. However, a careful reading of the study provides a much more nuanced viewpoint. For example, the fact that the study conditions were so tightly controlled makes it difficult to translate these findings to the real world.
  • In fact, the authors of the study acknowledged that multiple clinical studies show this almost never happens in the real world. These studies show that most people regain the weight they have lost on low-carb diets. More importantly, the rate of weight regain is virtually identical on low-carb and low-fat diets. Consequently, the authors of the current study concluded “…translation [of their results to the real world] requires exploration in future mechanistic oriented research.” Simply put, the authors are saying that more research is needed to provide a mechanistic explanation for this discrepancy before one can make recommendations that are relevant to weight loss and weight maintenance in the real world.
  • The authors also discussed the results of their study in light of a recent, well-designed 12-month study (CD Gardener et al, JAMA, 319: 667-669, 2018 ) that showed no difference in weight change between a healthy low-fat versus a healthy low-carbohydrate diet. That study also reported that the results were unaffected by insulin secretion at baseline. The authors of the current study noted that “…[in the previous study] participants were instructed to minimize or eliminate refined grains and added sugars and maximize intake of vegetables. Probably for this reason, the reported glycemic load [effect of the diet on blood sugar levels] of the low-fat diet was very low…and similar to [the low-carb diet].” In short, the authors of the current study were acknowledging that diets which focus on healthy, plant-based carbohydrates and eliminate sugar, refined grains, and processed foods may be as effective as low-carb diets for helping maintain a healthy weight.
  • This would also be consistent with previous studies showing that primarily plant-based, low-carb diets are more effective at maintaining a healthy weight and better health outcomes long-term than the typical American version of the low-fat diet, which is high in sugar and refined grains. In contrast, meat-based, low-carb diets are no more effective than the American version of the low-fat diet at preventing weight gain and poor health outcomes. I have covered these studies in detail in my book “Slaying The Food Myths.”

Consequently, the lead author of the most recent study has said: “The findings [of this study] do not impugn whole fruits, beans and other unprocessed carbohydrates. Rather, the study suggests that reducing foods with added sugar, flour, and other refined carbohydrates could help people maintain weight loss….” This is something we all can agree on, but strangely this is not reflected in the headlines you may have seen in the media.

The Bottom Line

 

  • A recent study compared the calories burned per day on a low-carb, moderate-carb, and high-carb diet. The study concluded that the low-carb diet burned significantly more calories per day than the other two diets and might be suitable for long-term weight control. If confirmed by subsequent studies, this would be the first real evidence that low-carb diets are superior for maintaining a healthy weight.
  • However, the study has some major limitations. For example, it used a methodology that may overestimate the benefits of a low-carb diet, and it was performed under tightly controlled conditions that can never be duplicated in the real world. As acknowledged by the authors, this study is also contradicted by multiple previous studies. Further studies will be required to confirm the results of this study and show how it can be applied in the real world.
  • In addition, the kind of carbohydrate in the diet is every bit as important as the amount of carbohydrate. The authors acknowledge that the differences seen in their study apply mainly to carbohydrates from sugar, refined grains, and processed foods. They advocate diets with low glycemic load (small effects on blood sugar and insulin levels) and acknowledge this can also be achieved by incorporating low-glycemic load, plant-based carbohydrates into your diet. This is something we all can agree on, but strangely this is not reflected in the headlines you may have seen in the media.
  • Finally, clinical studies report averages, but none of us are average. When you examine the data from the current study, it is evident that some participants burned more calories per hour on the high-carb diet than other participants did on the low carb diet. That reinforces the observation that some people lose weight more effectively on low-carb diets while others lose weight more effectively on low-fat diets. If you are someone who does better on a low-carb diet, the best available evidence suggests you will have better long-term health outcomes on a primarily plant-based, low-carb diet such as the low-carb version of the Mediterranean diet.

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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