Friday, March 4, 2011

Got Calcium?

Plenty! No thanks to Heidi Klum (no offense ms. Heidi but do you even drink milk!?!) and the masses of other stars lining up for the "Got Milk" Campaign.

A common question I’ve been asked when telling people I’ve stopped eating dairy (after hearing them go on and on about not being able to live without CHEEEEEEEEESE!) is: “But what about your calcium, aren't you afraid of osteoporosis?!” Here’s the deal: calcium is highly misunderstood. Whether it is because since we were children we’ve been taught to drink milk or else!!!! OR that people just don’t have the time to care about what it’s really about OR you hated freshmen biology... I don’t know, but lucky for you, I am a Bio Chick, and I am here to help you out. I'll make sure you understand all about the acid/base balance, intake vs excretion, and all the math that goes along with it--- ok, maybe not ALL of it, but some of the math!

Calcium is soft gray alkaline earth metal, and it is essential for living organisms. It is particularly important in cell physiology, where the movement of calcium into and out of the cell’s membrane functions as a signal for many cellular processes. The movement of calcium in this way helps the heart pump, your legs run (muscle function), the feeling of happiness (neurotransmitter release- remember the “happiness hormone” Serotonin from the WWGD post?), and even sexual attraction (hormone release and nerve transmission). Amazingly, only 1% of your body’s calcium helps these processes, the other 99% is stored in your teeth and bones. 

So now that we know how important this little guy is, let’s learn about where we can find him outside of the Dairy Barn! 

Since the most common sources of calcium in the AMERICAN diet are dairy and grain products, we Paleo-eaters turn back to our ancestors and Mother Nature for calcium. You think Grok got his calcium drinking jugs of milk and pints of yogurt or fortified OJ? I don't think so--- He was running around hunting prey with plenty of calcium in his bones, and no Milk in sight. There is plenty of calcium to be had from vegetables, fruit and seafood. Rhubarb, for example, contains 348mg of calcium per 1-cup serving and a 4-oz. salmon steak provides 225mg. A 1-cup serving of kale (which has a better absorption rate than milk along with containing several other vitamins, minerals and nutrients) supply more than 100mg of calcium. Other fruits and vegetables that provide significant sources of calcium include broccoli, seaweeds (kelp, wakame, and hijiki- check your Asian supermarkets or online!), nuts (almonds and sesame seeds), figs, and oranges. Good seafood choices include oysters, clams, shrimp and haddock. There is also the often overlooked store of calcium in the EGGSHELL (YES, the eggshell!!); which can be ground into a powder and mixed into meals and smoothies!

How much calcium do we need, really?

The amount of calcium required per day is mostly dependent on age and sex. Children, aged 4 to 8, require 800mg per day while adolescents, aged 9 to 18, require 1,300mg and adults, aged 19-50, require 1,000mg. While, adults aged 51 or older, pregnant or nursing women and postmenopausal women require 1,200mg per day (according to the University of Michigan Health System). WOW! That’s a lot of calcium! According to Dr Cordain, the RDA, recommended daily allowance,  is higher than one would need when eating according to the Paleolithic diet. This is because of the following 6 facts:

1. The absorption rate from brassica vegetables (e.g. Kale) is slightly higher than from milk, meaning although it may have less calcium, you actually get more from it.

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 is net acid yielding: this increases calcium excretion (meaning loss of Calcium in the Standard American Diet )

3. The Paleo Diet is a high protein diet and this increases intestinal calcium absorption and has an anabolic effect on bone (meaning it builds bones up)

4. By avoiding grains, you decrease anti-nutrient intake, such as phytates, which decrease magnesium, calcium, and zinc absorption. (See my post about BEANS!)

5. The Paleo Diet is a low glycemic load diet and as so, it does not promote Hyperinsulinemia as a high grain diet (high blood insulin levels cause urinary calcium loss)

6. Milk has a high Insulinotropic effect, therefore it may lead to an increase in urinary calcium excretion, for the reason outlined above.

So, what happens if we don’t get enough calcium, as many of those not eating Paleo worry for us?

Long-term calcium deficiency can lead to Rickets (a softening of the bone seen in children), poor blood clotting and in the case of a menopausal woman, it can lead to osteoporosis (deterioration of the bone and increased risk of fractures), while a lifelong deficit can affect bone and tooth formation. Oh, no--- I said it: the dreaded Osteoporosis!!!! No need to fear my paleo friends, while the National Osteoporosis Foundation says, "Calcium plays an important role in building stronger, denser bones early in life and keeping bones strong and healthy later in life,” I beg to ask you this question:

how is it that our country has the highest intake of calcium in the world, yet we also have one of the highest rates of osteoporosis.

Wait--- what!? That can’t be true… can it? Yes, it is true!!! This is because bone mineral content is not solely reliant on calcium intake but also upon the net calcium balance (Total Body Calcium = CALCIUM intake - CALCIUM excretion). Many people forget about the excretion side of the calcium equation! (I’m going to let Dr. Cordain explain the equation in detail) "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." Meaning, that while your overall intake of calcium while eating Paleo might be less than the RDA, you are actually getting more benefit from it: quality over quantity! 

One last thing I'd like to touch on before bringing this behemoth post to an end: bone health is about more than calcium: reasonable sun exposure and frequent weight-bearing activity are just as important to bone health as calcium, while smoking is detrimental to it! 

Vitamin D is necessary for the body to absorb Calcium. Vitamin D is naturally present in very few foods, thankfully it is produced when ultraviolet rays from sunlight strike the skin, triggering Vitamin D synthesis. Vitamin D obtained from sun exposure, food, and supplements is biologically inert, meanign it can't do anything until it is "unlocked". It is first unlocked in a reaction in the liver, followed by a reaction in the kidneys. Vitamin D promotes calcium absorption in the gut, therefore without enough vitamin D, calcium cannot be absorbed from the diet. Without sufficient vitamin D, the body must take calcium from its stores in the skeleton, which weakens existing bone and prevents the formation of strong, new bone. Recent studies have shown that the risk of osteoporosis is lower for people who are active, and especially those who do weight-bearing activities at least three times a week. How can exercise prevent osteoporosis? Muscle pulling on bone builds bone, so weight-bearing exercise builds denser, stronger bones. Exercise can also help you maintain bone density later in life. The best exercises for building bone include weight-lifting, jogging, hiking, stair-climbing, step aerobics, dancing, racquet sports, and other activities that require your muscles to work against gravity. Swimming and simply walking, although good for cardiovascular fitness, are not the best exercises for building bone.

So remember your daily Vitamin D, and get out there and bust a move! Carry those groceries, give your son a piggyback ride, or just get in a few push-ups!!

how do you get your calcium? --- tell us your favorite paleo source of calcium and a recipe you like to use with it!


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