A common criticism of the paleo diet is that it doesn’t provide an adequate amount of dietary calcium. Yes U.S.News Best Diets, I’m looking at you! But paleo advocates defend the diet and suggest that you can in fact get sufficient calcium by including plenty of this and that in your daily meals and remind us that our mineral absorption is much better due to the reduced amount of phytates in the food we eat and our healthier gut. They’re not wrong but it’s not as simple as wolfing down multiple cans of sardines and drinking litres of kale juice. In this post I want to go over calcium basics, why we need it, where we get it and how we make sure our bodies make the best use of it.
Calcium is the 5th most abundant element in the body, residing in our skeleton as well as blood and tissues. It supplies the strength to our 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 osteoporosis – weak and brittle bones –which is caused by the body using the calcium from bones when it notices that not enough is circulating through the system. Consuming enough is especially important for growing kids and teenagers while their bones are still forming, and older women who lose bone density quicker after 50.
Daily dietary intake of calcium depends on the age and gender of the person. Here is a handy table of Australian recommendations:
|Babies 0–6 months||approx. 210mg (if breastfed)|
|approx. 350mg (if bottle fed)|
|Babies 7–12 months||270mg|
|Children 1–3 years||500mg|
|Children 4–8 years||700mg|
|Children 9–11 years||1,000mg|
|Adolescents 12–18 years (including pregnant and breastfeeding young women)||1,300mg|
|Women 19–50 (including pregnant and breastfeeding women)||1,000mg|
|Adults over 70||1,300mg|
Most people don’t get enough calcium, and not because they don’t consume enough dairy or other calcium rich foods or supplements, but because their bodies lack essential supporting vitamins and minerals for proper absorption. Come in calcium friends and enemies…
Calcium works best when combined with other nutrients that work in synergy to build and maintain strong bones – I call them calcium friends. They are vitamin D and magnesium and both influence calcium metabolism and absorption. Without these guys you might as well not bother with calcium at all. Well you should of course, but you really need all three for optimal absorption and utilisation.
Some integrative nutritionists recommend a ratio of calcium to magnesium close to 1:1 (e.g. if you take 1000 mg of calcium, you will need about the same in magnesium) but most stick to a 350-500 milligrams of magnesium per day guideline. You need around 1000-2000 milligrams of vitamin D, which you can get from sun exposure and certain foods like liver and oily fish. Magnesium and vitamin D are also responsible for maintaining many other body functions but we will save that for another post.
One thing to keep in mind is that calcium and magnesium can compete for absorption with one another if taken in doses higher than 250 milligrams each. That means you should ideally take each mineral at a different time or split the doses into smaller portions. Again, this is not an issue with food as most of the time you will be getting under 300 mg of each from one single meal. In fact, your body has a hard time absorbing large amounts of calcium all at ones so it’s always better to split your daily dose between meals rather than trying to get most of it from one dish.
There are also a few enemies to watch out for. Phytates or phytic acid is an anti-nutrient found in grains and legumes (not a problem for paleo folks), seeds, nuts and some vegetables. The body binds phytates to calcium as well as other minerals, which prevents their absorption. Soaking, aslo known as ‘activating’, nuts and seeds and cooking vegetables removes most of the phytates, making the calcium and other minerals more available to the body.
Other factors that can reduce calcium in your bones include high salt diet, 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 have a lot to do vitamins and minerals absorption.
Can you have too much calcium?
There is some reported risk of kidney and heart problems associated with too much calcium. The body can only handle about 600 milligrams of calcium at ones. Extra mineral can build up in the bloodstream and can cause a kidney stone. And based on a few recent studies, there is a chance of calcification of coronary arteries in susceptible individuals. Don’t be alarmed as we’re talking about calcium consumption over 1500-2000 milligrams per day for a period of time and that’s pretty hard to do. In my eyes a varied paleo diet provides just enough.
It’s always better to get calcium from real food than from supplements because you will consume other nutrients along the way and the dietary calcium is more easily digested.
Dairy products are without a doubt the highest source of calcium and often contain other nutrients required for better absorption, such as vitamin D. However, it has also been reported that consuming too much calcium from dairy alone can reduce its absorption, and often only 25-35% of the mineral is used by the body as a result. You need plenty of fruit and vegetables high in alkaline-forming minerals such as potassium (basically to maintain a neutral PH level) to enable bones to hold on to calcium.
Just because you stop or drastically reduce dairy consumption doesn’t mean you will start popping and cracking all over the place. You can maintain healthy bones and teeth with a varied plant, fish and animal based diet, plenty of sunshine and maybe, just maybe, a little supplementation. Here is chart to help you navigate through dairy and non dairy, paleo friendly calcium rich foods.
As you can see, there are plenty of options for non dairy sources of calcium.
Foods high in magnesium and vitamin D
Magnesium: pumpkin seeds, dried herbs, dark chocolate (YES!), sesame seeds and tahini, brazil nuts, almonds and cashews, molasses, edamame, avocados, bananas, spinach, oysters, broccoli, artichokes, dates, okra, coconut milk, sheep and goat milk, prunes. Gee, looks a bit like the calcium rich food list. Coincidence? I think not.
Vitamin D: besides sunshine you can get vitamin D from such foods as liver, cod liver oil, oily fish such as salmon, herring and sardines, caviar, oysters, eggs, mushrooms, prawns and even salami and sausages.
So does paleo diet provide enough calcium?
Logistically, it’s a lot easier to use a combination of dairy and non-dairy food sources to get your daily intake of calcium as it’s easier to mix things up. You have to work a little harder without dairy, legumes and soy products but it’s possible. Below are two sample paleo meal plans to show how you can get enough calcium.
1) Cooking vegetables will remove any present phytates that can prevent calcium absorption, which is important for tubers and some greens like broccoli and green beans.
2) Nuts and seeds are high in calcium but they are also high in phytates so it’s best to soak and roast prior to eating, especially pumpkin seeds, sesame seeds, almonds and brazil nuts. Learn more about phytic acid here.
3) Canned sardines and salmon are very high in calcium but most of it comes from the bones. That means you shouldn’t be throwing those away and instead mix them in with the flesh, they’re small and soft enough to eat safely.