A common criticism of the Paleo diet is that it fails to provide an adequate amount of dietary calcium. Paleo advocates defend the diet and suggest that it is possible to obtain sufficient calcium by including certain whole, nutrient dense foods in your daily meals. They further emphasize that mineral absorption on a Paleo diet is particularly high due to the reduced amount of phytates and anti-nutrients in the foods consumed coupled with a healthier gut.
Can you get enough calcium on a Paleo diet?
What are the best non-dairy, calcium-rich foods?
Is calcium the only mineral necessary for bone health?
Calcium is the 5th most abundant element in the body, found in your skeleton as well as blood and tissues. It supplies the strength to your bones and teeth and plays a crucial role in other functions of the body such as the nervous system, heart, muscles, blood clotting and enzyme function.
Calcium deficiency can lead to weak and brittle bones and eventually osteoporosis. This occurs when the body leaches calcium from bones to elevate low circulating calcium levels. Consuming sufficient calcium is especially important for growing children whose are still forming, and older women who tend to lose bone density peri-menopausally.
The science on calcium is largely undecided and it is a surprisingly controversial nutrient. The government’s guidelines for calcium intake range from 1,000 to 1,300 mg daily for adults, but some experts suggest that only 600-800 mg of calcium daily is needed for healthy bones. Others argue that the bioavailability of calcium from different foods will affect how much calcium you actually need to eat in order to get what you need on a daily basis.
Most people fail to get enough calcium. This is not because they do not consume sufficient dairy or other calcium rich foods or supplements, but rather due to the lack of essential supporting vitamins and minerals for proper absorption.
Factors Affecting Calcium Absorption
Calcium works best when combined with fat-soluble vitamins, like A, D, and K – specifically K2 as well as magnesium. If you are consuming organ meats—particularly liver, lard, grass-fed butter, and maybe even some cod liver oil, you are already ahead of the curve in terms of the fat-soluble vitamins in your diet.
These fat-soluble vitamins are crucial for the deposition of calcium into bones to strengthen the mineral density and to fight fractures. Vitamin K2 for example, activates a protein called osteocalcin, which attracts calcium into bones and teeth. Without K2, the calcium you are ingesting has a difficult time knowing where to go and can remain circulating in your bloodstream. This can result in calcium being deposited onto the arterial walls. Molecules such as matrix GLA proteins, or MGPs, need vitamin K to function, and their purpose is also to help calcium get where it needs to go.
In order to produce osteocalcin (a non-collagenous protein found in bone and dentin) and MGPs, you need vitamin A, vitamin D. Vitamin K2 is the activator. If you are deficient in these nutrients, you cannot absorb all the calcium you are eating or supplementing with, because those proteins that take the calcium from your gut to other places in our body cannot be activated.
Supplementation of these vitamins is an option as lifestyle factors and geographical location can prevent you from getting adequate levels of Vitamin D naturally, from the sun. Liver and cod liver oil are good a source of Vitamins A & D. Vitamin K2 is found in free-run eggs, and cheese, particularly grass-fed cheese. If you are able to tolerate dairy, this is a solid source of Vitamin K2 and calcium (an example of nature providing nutrition along with the by-products needed to use it!!)
Phytates or phytic acid is an anti-nutrient found in grains and legumes, seeds, nuts and some vegetables. The body binds phytates to calcium as well as other minerals, which prevents their absorption. Soaking, nuts and seeds and cooking vegetables removes most of the phytates, making the calcium and other minerals more available to the body. The Paleo diet removes many of the foods with high amounts of phytic acid, resulting in better nutrient availability and absorption.
Other factors that can reduce calcium in your bones include too much fibre, too much caffeine (more than six cups per day), excessive alcohol, smoking and low levels of physical activity.
The health of your gut lining and how well you absorb nutrients will also determine your vitamin and minerals absorption.
Paleo Calcium Sources
Contrary to popular myth, a high-protein diet has been shown to increase the absorption of calcium( 1; 2; 3; 4). If you are concerned with getting enough calcium, ensure your protein consumption is adequate.
Eating calcium-rich foods in the context of a low-anti-nutrient diet, will result in a much higher absorption rate than on a standard American diet where grains and legumes, along with other anti-nutrient rich foods are consumed regularly, even in the presence of calcium. If you are getting adequate fat-soluble vitamins and eating green, leafy vegetables and some bone-in fish, and nuts and seeds on a regular basis, you are eating enough protein, and concentrating on good sources of fats, you are getting adequate amounts of calcium in your diet and metabolized by your body. Of course, if you tolerate dairy, raw, unpasteurized sources (especially cheese) is a really good way to get more calcium in your diet, but not necessary as long as you are following a well-formulated Paleo protocol.
Whole Foods & Calcium Content
On a vegetarian or vegan diet getting sufficient calcium can be a challenge, but even for omnivores and Paleo enthusiasts, the leafy greens and vegetarian sources, like nuts and seeds can pose hurdles. If you are consuming the majority of your calcium from leafy greens, some of their inherent anti-nutrients that can block the absorption of calcium. This includes phytates and oxalates.
If most of your calcium is from those plant foods, you are probably not absorbing it as much as you think, or, alternately, you will need to eat really large amounts. Cooking vegetables will reduce the amount phytates. This is important for tubers and some greens like broccoli and green beans. It is best to soak and roast nuts and seeds prior to eating to reduce phytate content. This is especially important for pumpkin seeds, sesame seeds, almonds and brazil nuts.
Bone-in fish is really the optimal calcium source. This can include canned of salmon with the bones in, or sardines that have the bones in. As an added bonus you will be getting vitamin D from the fatty fish - both the bioavailable calcium and the fat-soluble vitamin that will help absorb it in one small package.
Obtaining calcium from real food sources along with a focus on fat soluble vitamins as opposed to supplementation is preferred. The calcium will be consumed with other nutrients and co-factors and dietary calcium is more easily digested. Studies have shown that calcium supplementation increases the risk of atherosclerosis, which is the hardening of the arteries. I would think this is due to the fact that people are just taking calcium alone without being concerned about the fat-soluble vitamins, especially when it is in the form of a calcium supplement. There is nothing else in there. This calcium might not end up where it is meant to, in the bones and teeth, and instead, ends up in the arteries. Weight-bearing exercise and getting adequate sunlight are very important for bone health too.
A nutrient rich Paleo diet can provide adequate calcium for health and bone strength without the inclusion of dairy. Vary your food choices and include lots of fish and seafood, organ meats, greens, fruit, some nuts and seeds. Your Paleo diet will promote optimal absorption and utilization of your calcium resulting in a strong, and healthy body!