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Magnesium: A Piece of the Nutrition Puzzle


By Mary Kay Holloway, RDN, LDN, Dietitian at the Community Cancer Center

Good nutrition from food is very important to our health and wellbeing. Good nutrition can be compared to a 5,000+ piece jigsaw puzzle.

The puzzle box contains many pieces that connect with each other, and the picture on the front of the box shows what the pieces will make.

The pieces get twisted, turned, pushed, and pulled to find a linking piece, forming small groupings. Where these groupings fall in the whole picture can be complex and somewhat of a mystery. Likewise, nutrition research and marketing twist, turn, push, and pull food and food nutrients — making small groupings that we try to fit into a bigger picture, only to find that this too, is complex and somewhat of a mystery.

Magnesium is one of those nutrients/minerals that fit into a scenario like this. Let’s look at magnesium and why it’s an important piece of the nutrition puzzle.

Magnesium is a mineral that is abundant in our body. It is used for over 300 reactions which include energy and metabolism, muscle health (the heart is a muscle), regulation of glucose and blood pressure, bone health, migraine headaches, asthma, and pregnancy complications.

The adult daily requirement for magnesium ranges from 300mg to 400mg each day. According to the National Health and Nutrition Examination Survey (NHANES), the 2005–2006 survey indicates that nearly one-half of American adults do not get the daily requirement of magnesium from food each day. Magnesium absorption is affected by a variety of medical conditions, medications, caffeinated drinks, alcohol, refined sugar, and stress. An inadequate intake combined with poor absorption decreases magnesium levels in the body. The current method to measure magnesium is using a blood test. However, this does not measure the level in the cells of the body, which adds to the complexity of the puzzle.

Magnesium is rarely part of a conversation about nutrition to prevent cancer. However, magnesium interlocks with so many puzzle pieces that it is part of the whole picture of nutrition in cancer prevention and survivorship. For example, new research has shown that magnesium is beneficial to our Vitamin D status, and other research has shown low Vitamin D may be linked to breast cancer and other cancers. Many cancer survivors have a risk for osteoporosis. Magnesium is needed to fight osteoporosis in conjunction with calcium, Vitamin D, and other nutrients. Also, many chemotherapy drugs cause magnesium levels to become so low that replacement is required.

The food sources of magnesium contain hundreds of other nutrients, beyond vitamins and minerals, known to be protective against cancer risk. Magnesium is found in foods such as seeds, nuts, beans, unprocessed whole grains, low-fat dairy, and green leafy vegetables. Highly processed food lowers the amount of magnesium. For example, one slice of white wheat bread has 7 mg of magnesium compared to one slice of whole grain bread which contains 22 mg. Although not ideal, supplementing with magnesium will help until the food sources become a part of the regular lifestyle.

The nutrition puzzle is complex and different for everyone. Magnesium is a mineral used in multiple ways by our body and is needed for good health. Small improvements in the quality of food eaten can help to improve our health. Take the steps necessary to increase food sources of magnesium, which will provide many other nutrients to protect against health problems, including cancer.

The Community Cancer Center offers a variety of supportive and educational groups and programs, free of charge, to help patients and families cope with cancer and its effects. For more information go to their website at