Protein is one of the three macronutrients your body needs for health. Carbohydrates and fat are the other two. Unlike carbs and fat, protein isn’t the main macronutrient your body taps into for energy. Your body primarily runs on carbohydrates and fats except under special circumstances. Normally, you use less than 6% of the protein you consume through diet as a fuel source. However, you tap into protein more during periods of starvation or with excessive exercise in a glycogen-depleted state.
But let’s not underestimate the importance of dietary protein! You need the amino acids from protein for muscle repair and for preserving and building muscle tissue in response to exercise. Plus, protein has a variety of other functions in the human body. For example, enzymes, antibodies, and the structural components of cells are made of protein. People who exercise need more protein, as much as twice the amount, that dietitians recommend for sedentary folks. The amount they recommend for inactive people is around 0.8 grams per kilogram of body weight daily. If you strength train or do high-intensity exercise, you may need as much as double this amount each day to allow your body to avoid a catabolic state and to help with exercise recovery.
It’s clear we need more protein for maintaining and building muscle but what about protein for bone health? Like muscle, your bones undergo continuous remodeling, the breakdown of old bone and the creation of new. In fact, this process takes place throughout life, just as it does with muscle. Your bones need amino acids from protein and minerals, like calcium, to complete this process. The matrix of every bone in your body is made up of protein and you need the amino acids that protein offers for bone growth and maintenance. Therefore, you might wonder whether consuming more protein can help you keep your bones healthy and lower your risk of osteoporosis. What does science say about this?
Protein and Bone Health
Initially, research suggested that consuming a diet high in protein, particularly animal protein, might be harmful to bone health. This idea gained support after studies showed that consuming more protein increased the amount of calcium that entered the urine. Therefore, researchers hypothesized that high protein intake boosted the breakdown of bone and the calcium released from the bone was excreted in the urine. Therefore, they thought the calcium came from bone tissue and was a marker of greater bone breakdown. However, more recent studies show a diet higher in protein increases calcium absorption from the gut. So, the calcium in the urine after a high-protein meal comes from the greater amount of calcium entering the body after eating a meal high in protein.
In fact, the tide has shifted so much that experts now believe that consuming more dietary protein, above the recommended daily intake, may help prevent bone loss and stave off osteoporosis. That’s a big shift in thinking! But when you consider that protein increases calcium absorption, it’s not surprising that it might be beneficial for bone health. In fact, an analysis of multiple studies showed that consuming protein above the recommended daily intake may lower the risk of bone loss and hip fractures.
Another way protein may boost bone health is by increasing the production of IGF-1, known as insulin-like growth hormone one. IGF-1 is linked with bone and muscle health and also enhances the absorption of calcium from the gut. One large study followed women during and after menopause. It found that subjects who consumed more protein, regardless of whether it was animal or plant-based, had a lower risk of developing a wrist fracture.
Animal versus Plant-Based Protein and Bone Health
Does the type of protein matter? You may have read that plant protein is better for the health of your bones than animal protein. However, research suggests that they both may be beneficial for bone health. One type of plant-based protein is soy, one of the few plant-based proteins that contain all the essential amino acids. Soy is also rich in estrogen-like compounds called isoflavones. Due to the weak estrogen-like effects of isoflavones, experts thought soy protein may be more favorable than animal protein for preserving bone health. However, a 2018 analysis of multiple studies found no difference between the two types of protein in terms of their impact on bone health. One caveat, the studies were short and the number of subjects was limited.
But other studies also support the idea that protein, regardless of its source, is beneficial for bone health. Just recently, a review published in the journal Osteoporosis International suggested that consuming more protein, both plant-based or animal-based, is linked with better bone density and a reduction in the risk of hip fractures. However, they also point out that these benefits are dependent on people consuming enough dietary calcium.
The Bottom Line
A high-protein diet that contains more protein than the RDA may not be harmful to your bones after all. In fact, it may be beneficial, regardless of whether it’s animal or plant-based protein. On the other hand, plants are a good source of magnesium, another mineral that supports healthy bones. Plus, consuming more plant-based protein is beneficial for other reasons. Plants are a good source of fiber and phytonutrients that you don’t find in animal-based foods.
Also, be aware of your risk factors for osteoporosis. Established risk factors for osteoporosis include:
· Being Caucasian or Asian
· Having small bones or being underweight
· History of an eating disorder
· Smoking or using excessive alcohol
· Use of certain medications
· First or second-degree relatives who have had osteoporosis
· History of fractures
· Having certain health problems
· Smoking
· Using excessive alcohol
Be sure to talk to your doctor about your risk factors so the two of you can design a plan for reducing your risk.
References:
· Nutrition Today: May/June 2019 – Volume 54 – Issue 3 – p 107–115. doi: 10.1097/NT.0000000000000340.
· American Journal of Food and Nutrition, Vol. 4, No. 6, 2016, pp 138-149. doi: 10.12691/ajfn-4-6-1.
· J Am Coll Nutr. 2017;36:481–496.
· PLoS One. 2018; 13(2): e0192459.
· Osteoporosis International. September 2018, Volume 29, Issue 9, pp 1933–1948.
· Curr Opin Clin Nutr Metab Care. 2014 Jan; 17(1): 69–74.doi: 10.1097/MCO.0000000000000013.
Related Articles By Cathe:
Dieting to Lose Weight May Endanger Bone Health
5 Reasons to Ditch Restrictive Dieting
