Paleo Diet and Calcium

I’ve gotten a lot of questions from our female Crossfitters about the Paleo Diet and calcium intake. They are worried about osteoporosis, since the Paleo diet does not allow dairy products. The most recent issue of the Paleo Diet newsletter tackles this subject. I’m not going to reproduce the content of the newsletter, merely expand on some of the key topics in it.

Conventional wisdom dictates that lots of dairy products (milk, yogurt) be consumed in our to provide adequate calcium for strong bones. Turns out that conventional wisdom for osteoporosis is about as a effective as the conventional wisdom about low-fat diets. The National Osteoporosis Foundation estimates that 44 million Americans, or 55 percent of the people over 49, are at risk for osteoporosis. This despite the fact that the US has one of the highest calcium intakes in the world.

Turns out bone health depends on a number of factors besides calcium:

• Vitamin D – regulates calcium absorption and bone growth. Vitamin D deficiency contributes to osteoporosis. You can’t get Vitamin D through food. Your body actually produces it when exposed to direct sunlight. If you don’t get much sun, you need supplements.
• Physical Activity – Crossfit doesn’t just build strong muscles. Your body responds to mechanical stress by building stronger bones and connective tissue also.
• Micronutrient intake – adequate levels of magnesium, zinc, copper, folic acid, vitamin K, B2, B6, B12 all play a role in bone health (I got tired of linking back to Wikipedia, so you can look up each one if you want).
• Protein intake – protein increases intestinal calcium absorption, and has an anabolic (building) effect on bone.
• Calcium excretion – Moreover, when we talk about calcium balance, it should be pointed out that calcium intake is only part of the equation. We also have to consider calcium excretion, which can be increased by a diet that chronically elevates blood insulin levels (such as a diet composed of high glycemic load foods, such as sugar containing foods, potatoes and many grain based products, and by milk and fermented milk).
  
  Calcium excretion is also increased when people eat a net acid yielding diet, which is key to bone health. After the nutrients in the foods we eat are metabolized, they report to the kidneys as either acid or base. If the diet yields a net acid load, the acid must be buffered by the alkaline stores of base in the body, such as calcium salts, which are released from bone and then eliminated in the urine, gradually leading to osteopenia (low bone mineral density) and eventually to osteoporosis. (Ok, so this one I did just straight pull from the newsletter)

The Paleo Diet delivers on all of these nutritional concerns (except for Vitamin D as mentioned). Lean meat is a cornerstone of the prescription while the quantities of fruits and vegetables consumed provide a large punch of micronutrients and work to yield a net-base load on the body.