Magnesium: The Forgotten Nutrient?

Functions of Magnesium

Magnesium is often a neglected nutrient. Low intakes are common and are associated with cardiovascular disease, type 2 diabetes, and osteoporosis. Along with an adequate intake of potassium and calcium, these minerals favor a lower risk of hypertension.

50 to 60% of magnesium in the body is found in bone. The rest resides inside the body cells with a small percentage in the blood. It functions in over 300 enzyme systems, many of which involve the release of energy, proper functioning of nerves and muscles including those of the heart and in the many steps of DNA, RNA and protein synthesis. It also affects the metabolism of calcium, sodium and potassium.

How Much Do We Need?

The Recommended Dietary Intake (RDI) is 400 mg for adults and children over the age of 4. The Upper Tolerable Level (UL) is 350 mg from non-diet sources.

An intake below the RDA is commonly seen in the population but a blatant deficiency is rare. The use of diuretics can increase urinary loss and the use of proton pump inhibitors to treat gastroesophageal reflux disease GERD) can interfere with magnesium absorption.

Food Sources

The best food sources are:

Seeds and nuts

Garbanzo beans

Leafy greens like spinach

Processed foods are poor choices. For example, a cup of whole wheat flour contains about 166 mg. of magnesium. When that grain is refined and thus more processed, the white flour only contains 28 mg.

Magnesium Supplements

Since magnesium is not found abundantly in many foods, magnesium supplementation is popular and claimed to be beneficial for just about any disorder.

Research on the role of magnesium in other medical conditions is sparse. For example, magnesium levels in the body may alleviate the effects of osteoporosis. Dietary magnesium may have some benefit, but using supplements does not appear to have the same effect. The same may be true for its role in controlling hypertension. Its claims often include treating anxiety, ADHD, depression, and muscle cramps; however, most research does not report much help from supplements. One common side effect of magnesium supplementation is its laxative effect with some forms. Magnesium taurate and magnesium glycinate appear to not have this effect.

Always tell your doctor about any supplements you take. Dietary supplements are not regulated by the FDA, so buyer beware.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Magnesium Deficiency and Pancreatic Cancer?

English: Pancreatic Cancer Action logo (Photo credit: Wikipedia)

Magnesium

Description and Function 

Magnesium is a mineral that affects the metabolism of calcium, sodium, and potassium. About 50-60% is in bone. Most of the rest is inside cells. It is a cofactor for over 300 enzymes, many of which participate in the generation of energy as ATP from carbohydrate, fat and protein. It is necessary for the proper functioning of the nerves and muscles, including the heart. It is important for DNA and RNA synthesis and for almost every step in protein synthesis.

Food Sources

Magnesium is a component of chlorophyll and therefore found in leafy greens such a spinach and kale. Nuts, seeds, bananas and the germ and bran of whole grains are also good sources. Processed foods are generally poor sources. For example, removing the bran and germ of a whole wheat kernel reduces the magnesium content of a cup of white flour to only 28 mg, compared with the 166 mg in a cup of whole-wheat flour. One cup of whole grain cereal, spinach or legumes contain about 100 mg of magnesium.

Deficiency

According to my textbook, deficiency is rare in the healthy population, but does occur in alcoholism, kidney disease, and gastrointestinal disease. Some medications such as diuretics (commonly taken for hypertension) can contribute by increasing magnesium loss in the urine. Proton pump inhibitors (PPI‘s) taken to prevent GERD, may cause low blood magnesium by interfering with magnesium absorption. Talk to your doctor about any medications you take and their drug-nutrient interactions.

Deficiency symptoms include muscle weakness and cramping, irritability, anxiety and changes in blood pressure and heartbeat. Low blood levels of magnesium affect levels of blood calcium and potassium so some of the symptoms may be due to alterations in these minerals as well.

Nevertheless, the typical intake of magnesium in the U. S. is below the RDA of 400 mg/day for young men and 310 mg/day for young women. After 30 years of age, the recommended intake increases to 420 and 320 mg/day for men and women, respectively.

There has been no large systematic study of the adequacy of magnesium body stores in Americans. In 2009, the World Health Organization published a report that stated that 75% of Americans consumed less magnesium than needed. Some say that we have a nationwide magnesium deficiency, especially those who sell supplements. It would be helpful if the National Institutes of Health or the Centers for Disease Control and Prevention could fund serious research to determine the status of Americans’ magnesium body stores. I fully have supported getting our nutrients from the diet and not from supplements, most of which are unnecessary. However, the current American processed food diet as well as our fast food intake may warrant magnesium supplementation for some consumers.

Low intakes of magnesium have been associated with heart disease; type 2 diabetes, hypertension and osteoporosis.

Magnesium Supplements

There are no adverse effects of magnesium intake from foods, but supplements of all types may have some side effects. Some elderly patients who have impaired kidney function may suffer from toxic effects of magnesium-containing laxatives and antacids such as milk of magnesia. The Tolerable Upper Intake Levels (UL) for adults and adolescents over 9 years of age is 350 mg from nonfood sources of magnesium.

Calcium in the diet decreases absorption in the digestive tract; therefore, the use of calcium supplements can reduce the absorption of magnesium.

Source: Smolin, Grosvenor: Nutrition, Science and Applications, Third Edition, Wiley.

Little is known about the relationship of diet and pancreatic cancer. Mortality rates from pancreatic cancer are increasing and there is a great need for more research in its prevention.   FYI article follows on magnesium deficiency and its proposed association with pancreatic cancer.

CLICK HERE.

What About Magnesium?

food sources of magnesium: bran muffins, pumpkin seeds, barley, buckwheat flour, low-fat vanilla yogurt, trail mix, halibut steaks, garbanzo beans, lima beans, soybeans, and spinach (Photo credit: Wikipedia)

When I took nutrition courses, I don’t remember  learning much about magnesium.  When I taught nutrition courses, I was as guilty as my professors by not paying too much attention to this important mineral.

Magnesium is the fourth most abundant mineral in the body.  About half resides in the bones and the other half is contained in the cells.

One percent is found in the blood and highly regulated and maintained. Magnesium is involved in about 300 enzyme reactions.  It is needed for the metabolism of carbohydrate, protein, and fat, muscle and nerve function, healthy bones and a regular heartbeat.

How much do you need?

·      Women aged 19-30 need 310 mg/day

·      Men aged 19-30 need 400 mg/day

·      Women 31 and over need 410 mg/day

·      Men 31 and over need 420 mg/day

On average, females consume only about 70% and most males consume about 80% of these daily needs.

Food Sources

Whole grains:  Whole-wheat pita = 44 mg.

Vegetables: 2 cups of spinach = 47 mg.

Fruits: 1 banana = 37 mg.

Dairy: 1 cup of yogurt 27 mg.

Nuts: 2 tablespoons peanut butter = 49 mg.; 1 oz. almonds = 81 mg.

Eating these foods will provide over half of your daily needs. Milk, meat and eggs are also good sources.  Refined grains are poor sources since the germ of the grain is removed during processing.

Taking supplements may have some drawbacks – consuming large amounts may cause diarrhea, cramps and nausea. Because of this, the upper level from supplements is set at 350 mg for adults.

Deficiencies are rare since the kidneys compensate for low magnesium intake by excreting less of it.  Deficiencies may occur due to medications such as diuretics and some antibiotics.

Are there potential health benefits?  The research suggests:

·       Reduced risk for type 2 diabetes.  Magnesium plays a large role in carbohydrate metabolism and may influence the release and activity of insulin.  Low levels of magnesium are common in diabetics and may also contribute to insulin resistance.

·       Maintaining healthy blood pressure levels. A diet that’s high in fruits and vegetables, both of which are good sources of magnesium, has consistently been shown to lower blood pressure.  Studies with the DASH diet (Dietary Approaches to Stop Hypertension) have confirmed this effect.

·       Reduced risk for coronary artery disease.  Several studies have suggested higher levels of magnesium to lower risk for coronary artery disease, leading to heart attacks and strokes. There is also evidence that getting enough magnesium will help to prevent heart arrhythmia.  In a recent study, researchers measured the magnesium levels of 7,664 healthy adults using urine tests.  The participants were then followed for 10.5 years to assess the incidence of ischemic heart disease (IHD). Those people with the lowest urinary levels of magnesium were 70 percent more likely to die from IHD when compared to those with higher levels.  The authors concluded that magnesium levels are an independent risk factor  for IHD.   (American Journal of Clinical Nutrition, May 2013).

Some Tips on Getting Enough Magnesium

·       Spread peanut butter on whole-wheat crackers for a snack.

·       Add black beans to salsa for a veggie dip.

·       Add baby spinach to a salad.

·       Sprinkle chopped almonds on whole grain cereal in the morning.