It is inevitable. Every time someone asks me about nutrition and we begin to talk about dairy (and the why's behind the no-dairy recommend); I get the same question:
"If I eliminate dairy, from where will I get my calcium?"
No better answer than the one given by Dr. Cordain. Read on.
In the U.S. calcium intake is one of the highest in the world, yet paradoxically we also have one of the highest rates of bone de-mineralization (osteoporosis). Bone mineral content is dependent not just upon calcium intake but upon net calcium balance (calcium intake minus calcium excretion). Most nutritionists focus upon the calcium intake side of the calcium balance equation, however few realize that the calcium excretion side of the equation is just as important (i.e., how much of that calcium we take in is actually excreted!)
Bone health is substantially dependent on dietary acid/base balance. All foods upon digestion ultimately must report to the kidney as either acid or base. When the diet yields a net acid load (such as low-carb fad diets that restrict consumption of fruits and vegetables), the acid must be buffered by the alkaline stores of base in the body. Calcium salts in the bones represent the largest store of alkaline base in the body and are depleted and eliminated in the urine when the diet produces a net acid load. The highest acid-producing foods are hard cheeses, cereal grains, salted foods, meats, and legumes, whereas the only alkaline, base-producing foods are fruits and vegetables. Because the average American diet is overloaded with grains, cheeses, salted processed foods, and fatty meats at the expense of fruits and vegetables, it produces a net acid load and promotes bone de-mineralization. By replacing hard cheeses, cereal grains, and processed foods with plenty of green vegetables and fruits, the body comes back into acid/base balance which brings us also back into calcium balance. (In otherwords, good acid/base balance means lower levels of calcium excretion, which means we will retain MORE calcium!)
1. The absorption rate from brassica vegetables (e.g. Kale, broccoli, cauliflower, brussel sprouts, turnips) is slightly higher than from milk (without the inflammation issues caused by dairy) and as so (and also because they have numerous health benefits), we advise the daily intake of these foods.
2. A diet with lots of vegetables and fruit is net base yielding and in contrast a diet high in grains, cheese and salt and low in fruits and vegetables (which is a characteristic of the American way of eating) is net acid yielding and this increases calcium excretion. (are we getting it yet?? The more dairy/grains are replaced by vegetables/fruits, the more calcium we will retain!)
3. The Paleo Diet is a High protein diet and this increases intestinal calcium absorption and has an anabolic effect on bone, particularly in the context of a net base yielding diet.
4. By avoiding grains, you decrease anti-nutrient intake, such as phytates, which decrease magnesium, calcium and zinc absorption. (more grains=less calcium absorption. Less grains/more vegetables=more calcium absorption!)
5. The Paleo Diet is a Low Glycemic Load diet and as so, it does not promote Hyperinsulinemia as a high grain diet. It has been known since1975 that high blood insulin levels cause urinary calcium loss.
6. Milk has a high Insulinotropic effect, and as so it may lead to an increase in urinary calcium excretion.
In order to retain the calcium we ingest and prevent our bodies from excreting calcium, we need to replace grains/dairy with vegetables/fruits. It's that simple.