Long before almond and soy milk in every flavor, and those amazing kale chips you can get in health food stores, mothers used to tell their children to drink their milk and eat their spinach. We’ve already learned Mom was right about the milk; turns out she was right about the spinach too! Spinach is one of the best sources of Magnesium, and apparently Magnesium is good for your knees. A group of researchers decided to look at the relationship between knee arthritis and Magnesium levels.
Magnesium is a very important nutrient. Along with Calcium it’s crucial for good bone and muscle health, but since unlike Calcium your body can’t store it, a new supply is needed daily. It’s Magnesium which ensures that the Calcium you take in actually gets to your bones. Magnesium works to suppress a hormone called PTH produced by the parathyroid gland which pulls the calcium away from the bones to be stored in muscle. When Magnesium and Calcium are in the right balance to each other, a hormone called calcitonin produced by the Calcium assists in this suppression, insuring that adequate Calcium stays in the bone. For this reason, it’s thought that low Magnesium may be involved in Osteoarthritis.
The new study set out to establish a relationship between the amount of magnesium (Mg) in the blood and evidence of knee osteoarthritis (OA) on X-ray. To do this they did a cross sectional study of 2855 subjects. A value was assigned to establish what constituted OA on a knee X-ray. Subject’s Mg levels were evaluated using chemical luminescence. The subjects were divided into 4 groups based on their Mg levels, and the group with the lowest level was used as the reference. Once the confounders of Age, BMI and Sex were accounted for using multivariable logistical analysis, the Mg levels were compared to the knee X-rays. The relative odds of knee OA on X-ray was decreased by 0.72 times in the group with the highest Mg levels compared to the group with the lowest levels, demonstrating that higher Mg blood levels correlate to less knee OA.
The upshot? The connection demonstrated between knee arthritis and Magnesium blood levels are consistent with expectations based on what we know about the function of Mg. Obviously, it’s a much better idea to make sure you’re getting enough Mg in the first place, and importantly, making sure the Magnesium is in the correct balance with Calcium. Given Popeye the sailor’s legendary strength and agility, its a pretty good assumption that he didn’t suffer from knee arthritis or any other form of OA, so take Mom’s and Popeye’s advice – and eat your spinach!