Wednesday, February 10, 2010

Why We Don't Need Dairy - Nutritionally

Everyone already knows that calcium is key to strong bones and teeth. It's a little less known that it's required for nerve and muscle function as well as blood clotting. Ninety-nine percent of the calcium in the human body is stored in the bones and teeth while the remaining one percent is stored in the blood and other tissues. Calcium moves about in our bodies in two ways, from consuming it and pulling it from our bones. Extracting it from bones happens when blood levels of calcium drop too low, usually when it's been awhile since having eaten a meal containing calcium. Ideally, the mooched calcium will be replaced later on, but this doesn't always happen and replacing the borrowed calcium can't be accomplished simply by eating more calcium.

One of the most common questions a vegan will hear is "Where/how do you get enough calcium?" If we don't consume dairy then we must struggle to get this vital nutrient no? We listen to our televisions, schools, parents, governments tell us our whole lives that not only do we need calcium but we need to get it from milk, cheese, yogurt and all things dairy. It certainly seems like you need dairy to get to the amounts of calcium recommended. While we do indeed need calcium there are many ways in which to get it. Chances are good that we do not need quite as much as the US RDA suggests and there are other healthier ways to get it than the dairy overload diet more and more people are led to eat.

To look at the issue simply, milk from other animals is nutritionally too much for us. The milk produced by each mammal is especially formulated to fuel their infant's extremely high growth rate during those first weeks/months/years (depending on which mammal we are looking at). Cow's milk has more than four times the calcium content as human breast milk. We do not need this amount of calcium during our greatest growth cycle. Why would such a concentration of calcium, ideal for a baby not even of our species, be required when we stop growing bones as adults? Just look at the size of cows. Their bones are much larger than human bones . Comparatively we humans are tiny. Not once during our entire life span do we need to grow to the size of a cow.

Most mammals are weaned after this first big growth stage because they are able to finish growing and thriving on the diets of their parents and others of their kind. We drink milk as babies and normally by the time we reach the age of about 5 we stop producing the enzyme to digest milk, lactase. The ability to truly digest lactose (people who continue to produce lactase in sufficient quantities) occurs in only about one third of the world's population, mostly Caucasians. Which brings us to another issue, lactose intolerance. It is portrayed as an illness or a defect but it is in fact part of our natural maturation. We're supposed to grow out of milk. Our mommies don't need to provide us with milk anymore because we are big kids and can eat big kid foods and our bodies know this.

The consumption of cow's milk also means a big shot of saturated fat and protein at the same time. The jury is still out about protein and calcium but there seems to be some evidence of increased calcium loss through urine while also consuming lots of protein. So you might be dumping most of that calcium from that glass of milk or hunk of cheese literally down the toilet. Sodium also increases calcium loss, 5-10mg of calcium for each gram of salt. Depending on how the rest of your diet looks, again, all that calcium might be going right down the drain.

There are few studies on vegans and calcium. However we don't need lab results to find the evidence we need. The world picture fails to support benefits claimed by the dairy industry. Countries that have the highest traditional consumption of dairy products (United States, Sweden, Israel, Finland, and the United Kingdom) also have the highest rates of osteoporosis-related hip fractures. Places in the world with a traditionally low intake of dairy such as Hong Kong, Singapore, and countries in rural Africa have the lowest incidence of osteoporosis. Worldwide, the incidence of osteoporosis correlates directly and strongly with animal protein intake. The highly acidic nature of animal protein could be the major cause of bone loss in these animal intensive regions. We must also take into account that the calcium in cow's milk is supposed to come from the grass but most cows never see grass, never mind eat any of it. Their feed is supplemented with calcium. Since the cows are being fed supplements couldn't we not just supplement our own feed? The closer we look, whole idea that we need to drink milk becomes more and more unnatural.

So how much calcium do we need? A good question as the authorities cannot seem to agree. The US RDA states that we need 800-1000 mg of calcium per day. The World Health Organization puts it at 400-500 mg and Japan's recommendation is 600 mg and in the UK it's 700 mg. In the end I don't think exact figures are important. It is only recently, when humans started over engineering their food, that we have started worrying about specific levels of nutrients. Osteoporosis is also a recent problem. Coincidence? Couple that with companies and industries wanting to sell as much of their product as possible and it is clear that we are over complicating the matter. We have allowed ourselves to play mother nature thinking we could make food better. It is no coincidence that we have so many diseases (such as osteoporosis) that simply were not an issue before our over engineered consumer driven society emerged . You can get all the calcium you need without suckling at the teats of other animals.

While the amounts of absorbable calcium from vegetarian sources varies, it is clear that a diet containing a wide variety of foods (and if you are worried, a supplement – from vegetarian sources of course) will get you to any of the recommended calcium levels you subscribe to. To help you actually get the calcium where you need it keep in mind that vitamin D, and likely K, aid in the absorption of calcium. When blood levels of calcium begin to drop, the body responds in several ways. It promotes the conversion of vitamin D into its active form, which then travels to the intestines (to encourage greater calcium absorption into the blood) and to the kidneys (to minimize calcium loss in the urine). Get your vitamin D primarily from the sun just like most of the other animals. Animal products that claim high vitamin D collect it mostly through enriched feed or sun exposure, both of which we can do directly to ourselves. There is also the third option of eatting foods that contain some vitamin D. Essentially vegans are at no more of a disadvantage than omnivores to get enough vitamin D. If you do start taking a vitamin D supplement make sure it is D2 (ergocalciferol) which is vegan (usually derived from yeast), D3 (cholecalciferol) is animal derived (usually sheep's wool or fish oil). Vitamin K, which is found mainly in green leafy vegetables, likely plays an important role in calcium regulation and bone formation.

I'll give you a little reference so we have somewhere to start on this "we don't need no stinkin' dairy" journey but remember that these are not the only foods with these nutrients and ultimately you should be eating a wide variety of fruits, vegetables, nuts, legumes, and grains. In this way you can be sure to hit all your nutritional needs. In addition there are several vegan multi or specific vitamins available on the market to be found in your local coop, natural food store, mail order, or maybe even in your local chain supermarket.

Souces of Calcium in common veggie friendly foods:
Collards (1 cup) 357mg
Spinach (1cup) 291mg
Blackeyed Peas (1cup) 211mg
Calcium set tofu (3oz) 163mg
Canned Baked Beans (1cup) 154mg
Broccoli (280g – 1 stalk) 112mg
Green Peas (1cup) 94mg
Fortified Soymilk (1 cup) 93mg
Kale (1 cup) 93mg
Oranges (1 cup) 72mg
Almonds (1 oz - 24 almonds) 70mg

Sources of Vitamin K (mcg per 100g)
Cauliflower 3600
Brussels sprouts 800
Broccoli 800
Lettuce 700
Spinach 600
Tomatoes 400
Cabbage 400
String beans 290

What we hear coming at us from such trustworthy sources as our schools and our government is actually advertising from the dairy industry. They wish to continue selling as much of their product as they can. Yes, humans are omnivores. We can eat just about anything and get energy and nutrients from it. We're lucky like that. However, ethics aside (because this is primarily a post about nutrition and health), humans were not built to handle, over the long term, many of the things we feed ourselves, including dairy. Pay attention to who is doing the latest study claiming the latest breakthrough, a business studying it's own product is probably not the best source of reliable information on that product. When a popular yogurt brand tells you that "calcium helps you lose weight and yogurt is a good source of calcium!" remember that it's just a commercial meant to sell you yogurt.