Electrolytes are crucial for all sorts of bodily functions. Their ranks include sodium, potassium, chloride, and phosphorous; lists of electrolytes usually also include calcium; and they should also include magnesium. Yet magnesium is often overlooked, which is why one peer-reviewed study called it "the forgotten electrolyte."
It's an ironic designation, given Mg's crucial and central role. Mg is part of more than 300 biochemical reactions in the body; it's important for muscle and nerve function, heart health, immune strength, and bone strength.
Mg has special relevance for those with celiac disease, but is something I don't see talked about a whole lot. So today I want to focus on a series of related topics: Mg and celiac disease, Mg and the immune system, Mg and bones, Mg and athletes, Mg and getting glutened, and dietary sources of Mg.
Mg and Celiac Disease
About half your body's Mg is found in bones. The other half is in body cells and tissues. (Less than 1% is in the blood.) Dietary Mg is absorbed in the small intestine, the same area affected by gluten in those with celiac disease, so it's no surprise that there are implications there. But the impact is big. An early 1960s study found "great magnesium losses" in the stool of a patient with untreated celiac disease. Following a gluten-free diet, "all mineral balances were restored to normal." Studies since then have only backed up those early findings. A study published in the New England Journal of Medicine found a "striking magnesium loss" in the stools of those with untreated celiac disease—up to four times as high as dietary Mg intake. That same study found that "this remarkable loss was reversed by the institution of a gluten-free diet."
Mg and Your Bones
Plenty has been written about Mg and its importance for strong, healthy bones. But two studies from mid-1990s specifically looked at the situation for those with celiac disease.
The first study looked at the effect of a gluten-free diet on mineral and bone metabolism in women with celiac disease. With what we already know from the previous section, the results are not surprising: prior to following a GFD, the women exhibited signs of Mg deficiency and intestinal malabsorption of calcium; one year after following a GFD, "all biochemical variables normalized," although at that stage patients in the study hadn't yet seen actual increases in bone density.
The second study looked more closely at Mg deficiency, and its possible role in osteoporosis in those with celiac disease. Its findings were sobering. The study looked at patients with biopsy-proven celiac disease and followed them on a gluten-free diet and Mg supplementation. Among patients who entered the study with osteoporosis, those who followed a gluten-free diet and Mg supplementation for two years showed "a significant increase in bone mineral density." (Researchers noted that those with celiac disease may have lower levels of intracellular free Mg ions, which has a variety of important implications, even in patients asymptomatic on a gluten-free diet. Thus GFD plus Mg supplementation proved especially important.)
Mg and Immune Health
A number of studies—including from 1975, 1988, 1992, 1996, 2002, 2003, and 2007—all looked at the centrally important role that Mg plays in immune health. It is critical for both innate and acquired immune responses; it plays a role in inflammation (a more generalized, non-specific immune response familiar to those negatively impacted by gluten); it plays a role in anaphylaxis; it interacts with vitamin D (also implicated in celiac disease) to modulate the immune system; and it has implications for potentially immune-compromised individuals, including athletes and the elderly. In other words, Mg is pretty darned important for your immune system.
Mg and Athletes
A variety of studies from the late 1990s (such as here, here, and here) and the 2000s (here) found—not surprisingly—that Mg is very important for athletes. It helps to maintain immune strength, it helps to prevent inflammation, it helps to regulate muscle function (including a likely role in preventing muscle cramps), it helps maintain energy levels, and it improved overall athletic performance. (For more on athletes, gluten, and electrolytes, check out The Gluten-Free Edge: A Nutrition and Training Guide for Peak Athletic Performance and an Active Gluten-Free Life.)
Mg and Getting Glutened
Poke around the Internet, and you'll find lots of advice for how to help your body recover from being glutened. Take probiotics to help restore gut biota. Hydrate to replace water loss in diarrhea. Take glutamine to support gut recovery. And the list continues. But you might also consider adding magnesium to that list—either supplements or focusing on magnesium-rich foods.
Consider the story of a triathlete who contacted me a number of months ago. (I lost his email in a computer crash so some of the particulars are fuzzy, but the central details have stuck with me...) After being diagnosed with celiac disease, he switched to a gluten-free diet and had a notable improvement in performance in triathlons. At some point he was glutened in a restaurant, and despite doing everything "right" to help his recovery, he just couldn't regain his energy levels. One of the culprits turned out to be low Mg levels.
Given high Mg losses in those with celiac disease exposed to gluten, Mg's role in inflammation and immune health, and Mg's role in regulating energy levels and muscle and nerve function, we should all be more aware of maintaining healthy Mg levels in our diets and our bodies. Which leads me to...
Dietary Sources of Mg
Some have cautioned that a gluten-free diet can potentially be Mg-deficient. From my perspective, this is only a concern if your diet is heavily based on gluten-free junk food made from refined, process gluten-free starches. (Mg is contained in the germ and bran of grains, which are removed to make refined starches, hence the concern...)
However, many of the best dietary sources of Mg are also both naturally gluten-free and foods that could be part of a healthy diet anyway: dark green vegetables, some legumes (beans and peas), nuts and seeds, and whole gluten-free grains.
The following foods contain an estimated 10–20% of the average recommended daily value of Mg: almonds, spinach, cashews, soybeans, peanuts, baked potato with skin, blackeye peas, pinto beans, brown rice, millet. Lots of other great gluten-free foods (such as lentils, kidney beans, bananas, and more) are close runners up.
So make a commitment to give your body the Mg it needs. This "forgotten electrolyte" is important for anyone, but especially if you have celiac disease, are an athlete, are immune-compromised, have an intestinal malabsorption issue, or any combination of the above.