Low-Carb Lie: High-Protein Diet Damages Kidneys

by Jonny Bowden

Another criticism of low-carb (or high-protein) diets is based on the fact that higher levels of protein result in higher levels of calcium in the urine, leading some people to the erroneous conclusion that protein causes bone loss.

But a tremendous number of recent studies are showing something quite the opposite.

Want Strong Bones? Eat More Protein!

The Framingham Osteoporosis Study investigated protein consumption over a four year period among 615 elderly men and women with an average age of 75.

The amount of protein eaten daily ranged from a low of 14 grams a day to a high of 175 grams.

And guess what?

• The people who consumed more protein had less bone loss!
• Those who ate less protein had more bone loss, both at the femoral bone and at the spine.
• The study also found that "higher intake of animal protein does not appear to affect the skeleton adversely."

The truth is that calcium gets absorbed better on a higher-protein diet, even if there is somewhat more urinary calcium excretion.

High-protein diets in two recent studies resulted in significantly more calcium absorption than the low-protein diets, which were associated with decreased absorption.

Interestingly, the actual "low-protein" diet that caused decreased calcium absorption in these studies had about the same amount of protein that the government recommends for adults!

The authors concluded that this fact...

"raises new questions about the optimal amount of dietary protein required for normal calcium metabolism and bone health in young women."

And a recent study in Obesity Research looked at a high-protein versus low-protein diets to determine whether the protein content of the diet impacted bone mineral density. It did.

Bone mineral loss was greater in the low-protein group.

In other words, without enough protein, you just aren't going to build (and preserve) strong bones, and the definition of "enough protein" may turn out to be a lot more than we previously thought.

The Verdict on Protein: Not Guilty

So, how did protein get this bad reputation for causing calcium loss and osteoporosis?

It partly stems from something in the body called the acid–base balance.

• All foods eventually digest and present themselves to the kidneys as either acid or alkaline (base).
• When there is too much acid, the body needs to buffer it, and calcium is one of the best buffering agents.
• Meats—along with many other foods, especially grains— are known to be acid-producing;
• Hence the deduction that high-protein diets would cause a leaching of calcium from the bone in order to alkalize the acid content.

But here's the thing: we now know that if you take in enough alkalizing nutrients, this doesn't happen. 

If you balance your high protein foods with calcium (and potassium),you will not lose calcium from your bones!

An interesting side note: You can take all the supplemental calcium you want, but if you don't get enough protein, it's not going to make much difference to your bone health.

The studies are very clear on this: Extra calcium is not enough to affect the skeleton when protein intake is low.

In short, it doesn't matter if there is a little more calcium in the urine as long as the body is holding on to more calcium than it's losing (i.e., is in "positive" calcium balance). And it will do that when there's plenty of protein plus calcium
(and other minerals) in the diet.

The Bottom Line

Higher protein intakes do not cause bone loss or osteoporosis, especially in the presence of adequate mineral intakes. In fact, lower protein intakes are associated with more bone loss.

"Why are low-carb diets essential for weight loss?"

This entire email is predicated on the fact that a low-carb diet is essential for weight loss.

If you aren't sold on this fact yet then you should watch this funny little video that reveals how the first low-carb diet was actually recorded back in the 1800s...