What’s white, helps bones grow and stay strong, and goes great with cookies? Americans are taught from a young age to drink milk because it helps bones grow big and strong, but are we consuming too much? More importantly, if the Dietary Reference Intakes (DRIs) are higher than necessary, would our government tell us? The dairy industry is multi-billion dollar industry and supplies the government with a lot of money, through taxes-from what consumers pay for the milk, and on the profits the dairy companies make- and from large donations to the government and campaigns, so if milk consumption were to drop, the money the government receives would also drop. The government and the dairy industry use ploys like the calcium crisis and the weight loss campaign to the keep the consumption of dairy products high. However, all is not what it seems if the consumer scratches the surface of these stories. Many citizens feel that our government is here to take care of them when in reality the government is really just taking care of its best interests.
The food guide pyramid and the dietary guidelines are the government’s way of reaching out to the people and helping them make the best food choices through the government branch of the USDA, or the United States Department of Agriculture. The USDA was first involved in making the food pyramid in the early 1900’s when there actually was a cause for concern of malnutrition. The USDA looked at what America was producing and came up with a way to prevent malnourishment and support agriculture by promoting the consumption of a wide variety of foods. The 1977 Farm Bill explicitly stated that nutrition and health relate to US agriculture and deemed the USDA the leading agency of the government to conduct important nutrition research and education. However times have changed in the past hundred years and it might be about time for the USDA to step away from the recommendations and perhaps let the Department of Health and Human Services take over, as Americans are no longer in danger of being under nourished, they are now in danger of being over-nourished as obesity rates, as well as diabetes, heart disease, kidney disease, cancer, and many other nutrition-related diseases rise.
Yet that may not happen. Already, America’s farms are dwindling as the younger generations look for more glamorous jobs and many foods are imported from countries where labor is cheap and resources are still plentiful. The government will do anything in its power to protect what is left of the nation’s farmers, including promoting foods that may not be as beneficial as they’re made out to be, such as dairy products.
Dairy products are promoted as a way to build strong bones and teeth, and maybe even lose those few extra pounds along the way. While those promotions aren’t truly false, the numbers may be. No two organizations can agree on exactly how much calcium a person really needs. The current DRI for American adults is 1000 mg. In the UK and Europe the recommended intake is 700 mg, in Australia it is 800 mg, while the World Health Organization only recommends 400-500 mg/day. Why the differences? Calcium intake is based primarily on output, or excretion, and the balance of the two. There are several factors that increase the excretion of calcium and those factors are found in higher amounts in the Unites States. They will be discussed later.
Other influences on recommended intake values are the many short-term (a year or so- not nearly as reliable) and the few long-term (many years) studies that look at calcium intake and the prevalence of bone fractures. These studies look at calcium intake versus bone density. While the short term studies show that an increased consumption of calcium- usually through supplements- equals an increased amount of bone density, the long-term studies show that there is not a significant reduction in the amount of bone fractures and breaks. In fact, one of the most famous studies, the Nurse’s Health Study, showed that women who drank two or more glasses of milk a day were just as likely to fracture or break a bone as women who drank milk once a week or less. There is currently a study in process by the NIH with the Women’s Health Institute that may give us more answers, but the study will take a few years to finish. Another reason studies are not too reliable is that they don’t just focus on calcium and its effect on bones, because it would be too difficult.
While the best source of calcium is dairy products, calcium can be found in a variety of other foods as well. Canned salmon and tuna are good sources of calcium because of the soft, very tiny pieces of bone. Some dark, leafy greens such as kale, Chinese cabbage, and turnip and mustard greens are good sources of calcium. White beans and pinto beans contain some calcium. A lot of foods and juices are being fortified with calcium, such as cereals and orange juice. If nothing else, there are supplements. Of course, it’s not just the foods that contain calcium that are important, but whether or not the body can absorb the calcium from those foods. There are factors that that aid with calcium absorption, such as vitamin D, lactose, and protein- which are all found in milk, making it the best bioavailable source. Fortified foods and supplements are also good sources of bioavailable calcium. With plant foods, there are factors that inhibit absorption such as fiber, phytate, and oxalate, making them not very good sources.
Calcium is the structural component of bones and teeth, and also helps with muscle contraction, blood clotting and enzyme activation. Once ingested, the acidic environment of the stomach helps break the calcium away from the salts it is bound to in foods, then active (requiring ATP, or energy) and passive (no ATP needed) transport systems within the intestines absorb this important mineral. Once in the body, most calcium is deposited in the bones while a little is found in intracellular and extracellular fluids. Excess is filtered through the kidneys and excreted. The body receives the greatest benefits from calcium during the years of linear bone growth and the years immediately following, typically childhood through early adulthood.
99% of the body’s calcium is found in the bones, and bones are comprised of mostly calcium and also phosphorus, fluoride, magnesium, potassium and sodium, as well as proteins and water. The three main types of bone cells help build (osteoblasts), breakdown (osteoclasts), and maintain (osteocytes) bone structure, and are acted upon by hormones, such as PTH and estrogen. The cells make up both cortical (dense) and trabecular bone (spongy). Bone cells are constantly being remolded and replaced, and as the chemical structure is broken down, some of the calcium can be released into the blood to be filtered and most likely excreted. It is this turnover that ingestion must match, if not exceed. The average adult needs about 550 mg of calcium daily to meet average turnover needs.
A look at other countries and their calcium intake shows that many countries consume less calcium than Americans do, yet they also have less bone fractures. The theoretical reason behind this is the US has a much higher consumption of sodium, phosphorus, and protein- all of which are related to increased calcium excretion, and US citizens have lifestyle factors, such as smoking- which increases calcium excretion, and not enough exercise, especially weight bearing exercise- which helps increase bone mass. In fact, a reduction in intake of protein and sodium can lead to a decrease in need for calcium, as 1 gram of animal protein leads to urinary calcium of 1 mg, while 1 gram of sodium leads to urinary calcium of 15 mg. In other words, if someone reduced their intake of protein by 20 grams, and their sodium by 1.1 grams, a person would be able to decrease their calcium needs by 200 mg.
Since dairy appears to be the best source of calcium, why not consume it? Well, dairy products are high in saturated fat, cholesterol, some contain lactose, and there is also the issue of cow treatment and how it affects us. Saturated fat is one of the nutrients to avoid as it can lead to obesity and heart disease. Even if a consumer were to choose low-fat dairy products, there is still the issue of lactose, which up to 50% of the US population cannot digest. This is a huge amount of people, and most of them are ethnicities other than Caucasian. Lactose intolerance is the inability to digest the milk sugar lactose because the enzyme lactase is not present. Biologically speaking, this enzyme is not needed after about the age of 5 as the child should no longer be breastfeeding. Technically speaking, cow’s milk is made for baby cows not humans, so it is not the natural course of things to still be consuming milk at an adult age.
Then there is also the issue of milk being full of artificial hormones and antibiotics. Many cows are given a Bovine growth hormone created by Monsanto to increase the quantity of milk the cows produce, and cows are given antibiotics because industrial dairy cows are kept in close quarters and are generally allowed to wander around in areas contaminated with their own excrement. These hormones and antibiotics can be passed through the milk to us, and while it is unknown the exact implications of this, we’re seeing more antibiotic-resistant bacteria and young children, especially young girls, seem to be maturing at a faster rate.
Also, recent studies are showing that it is just as important to get enough vitamin D in the diet and the FDA is now allowing health claims on products that contain both calcium and vitamin D to protect against osteoporosis.
Calcium is an essential part of everyone’s diet, but it’s not just calcium that builds and maintains strong bones throughout a lifetime. In fact, there’s no benefit to consuming more calcium than the body actually needs. There are many other diet and lifestyle choices a person can make to ensure their bones don’t become osteoporotic. The government may continue to suggest three servings of dairy a day, and the dairy industry will continue to make sure the government backs them by shelling out big bucks, but it is truly up to each person how they meet their daily requirements of calcium, and all other nutrients. While the different recommendations may make it confusing as to how much the requirement of calcium is, I suggest about 800-1000 mg daily. If a person wants to meet their requirements through consuming dairy, so be it, but there are plenty of other options for those who can’t or won’t consume dairy products. I also recommend choosing organic milk if possible, because organic milk won't contain artificial hormones or antibiotics. If organic milk is out of your price range, at least look for milk that does not contain rBGH, as least while dairy companies are still allowed to label it as such. Also, choose low-fat dairy products such as skim or 1% milk, low-fat yogurt and low-fat cheese.
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