Dietary Reference Intakes (DRIs) developed by the Food and Nutrition Board at the Institute of Medicine of The National Academies, recommend that males and females ages 19-30 take in 400 mg and 310 mg of magnesium a day respectively. Males 31 and older should up their intake to 420 mg a day, and females 31 and older should increase their daily amounts to 320 mg.
The DRI also encourages pregnant or lactating women to boost their magnesium intake even higher and to consult their doctors for suggested amounts.
Sea vegetables (kelp), nuts and seeds, beans, soybeans and some seafood (crab, clams) generally contain higher levels of magnesium compared to other foods. Grains and pseudocereals like quinoa, buckwheat and brown rice will offer you a relatively high amount of magnesium as well. But the real winners when it comes to the most nutrient dense, magnesium-rich foods are fresh vegetables and dark leafy greens like chard, collards, and spinach. Nuts and seeds pack a big punch for their size when it comes to magnesium density too!
True or False: Organic Foods Contain More Magnesium
It is no surprise that choosing to buy organic dark leafy greens and vegetables, can cost you. But if you choose to not purchase organic produce will you pay in a different way? Does buying organic make a difference in terms of mineral (magnesium) content compared to conventionally grown crops?
According to the Environmental Working Group, conventionally grown spinach ranks second when it comes to produce containing pesticide residue.
While some studies conclude that organic food may or may not be more nutritious than conventionally grown, it is safe to say that buying organic can protect you from detrimental pesticides and herbicides that generally act as antagonists when it comes to magnesium absorption and can eventually block mineral absorption and lead to mineral deficiency.
Is Dietary Intake Enough?
Swiss chard contains a whopping 150 mg of magnesium per cup. But does that mean you are covered when it comes to adequate magnesium intake? Not necessarily. Lifestyle, physiological, and agricultural factors all play roles in how dietary magnesium is absorbed. A disappointing reality, but a reality nonetheless!
Let’s Explore Why
Mineral-rich foods are becoming an anomaly these days. High rates of soil erosion account for less magnesium in the soil which results in low mineral content in plant foods including magnesium.
Many fruits and vegetables have lost large amounts of minerals and nutrients in the past 50 years. For example, McCance and Widdowson’s epic compilation, the Composition of Foods, has tracked the nutrient composition of foods since 1940. Between 1940 and 1991, there was an average magnesium decrease of 24% in vegetables and 16% in fruits.
Some foods have seen more drastic declines than others. Carrots have lost 75% of their magnesium content. You would have to eat 4 carrots today to get the same magnesium in 1 carrot from 1940!
And that’s only one reason. The health of our digestive system is also a factor in whether or not we can adequately break down food to get the good stuff. Optimum absorption is key in making sure magnesium actually enters our cells!
Absorption of dietary magnesium isn’t guaranteed, though. Enzymatic function, stomach, and bowel health are key factors in the absorption process. From the beginning of the digestive system (oral cavity) to the very end (the anus), all parts need to be working efficiently (especially the small intestine) for optimum breakdown. Even if our digestive process is working perfectly, mineral content in food likely won’t be high enough to offer our cells optimum protection.
Cooking methods and refined foods can also account for magnesium loss. If we choose to fry that one cup of swiss chard instead of bake or lightly sauté it, we can cheat ourselves out of getting the magnesium we need.
Between mineral-depleted plant foods, compromised digestive systems, and popular denaturing cooking methods, optimizing our magnesium intake via food can become quite a challenge.
Ironically, magnesium needs magnesium to facilitate the absorption process. It’s imperative for helping to synthesize enzymes, repair tissue in our intestinal lining, and contribute to our parasympathetic nervous system health, for starters. In order for these processes to function properly in the first place, we need to have enough magnesium in our bodies to provide energy to get these physiological jobs done and done well.