Minerals and Bone Health
Minerals are essential for the formation of healthy and strong bones, with calcium, magnesium and phosphorus all vital for maintaining the strength of bones. However it is not just these well known minerals which have a bearing on the strength and health of your bones, and other trace elements all play important roles in the maintenance of healthy bone. Many scientific studies have linked deficiency in minerals to an increased risk of developing bone diseases.
Calcium is a vital mineral for ensuring that healthy bones are formed and maintained, with this mineral being the main constituent of bone. Calcium is required from the diet to ensure that healthy bones are maintained; however calcium alone is not sufficient to make sure the bones remain strong and healthy. In addition to calcium, you need to ensure your body has just the right amount of important trace metals such as boron, copper, zinc, magnesium, phosphorus, potassium and selenium as well as your full complement of vitamins.
Not all of these trace minerals have a direct effect on bone health, and many are useful in helping the body absorb other minerals from the diet, for the regulation of pH in the body, for hormone production and the synthesis of proteins. One thing we can be certain of, is that despite an excellent knowledge of minerals and bone health, many of the exact roles of these elements has yet to be discovered. All of these elements are part of an intricate system which needs to be kept in perfect balance. While your body will take care of most of that for you, it is important that you get sufficient quantities of these minerals from your diet. A deficiency in any of these elements can have a profound impact not only on the health of your bones, but on health in general.
Calcium and Bone Health
Calcium is the element which everyone associates with strong and healthy bones, and it is vital not just for the bones but for many biological processes in the body. Calcium compounds are the major mineral elements of bone, with this element helping to give the bones structural rigidity and strength. However calcium is needed for much more than bone health, and this element is vital for muscle contraction, cellular signalling and transport in and out of cells, for nerve health and nerve transmission and heart function. If dietary calcium levels are insufficient or blood calcium falls too low, the body will take the calcium it needs from healthy bones in order to maintain cell, nerve and muscle function. This will therefore lead to weakening of the bones.
The body may be able to produce a wide range of compounds and chemicals, but it is unable to produce elements such as calcium. Calcium must therefore come from the diet, and eating foods which are high in calcium is the best way to ensure that your body has sufficient levels of this important mineral. Calcium intake has been strongly linked with the prevention of osteoporosis and other bone weakening diseases.
However, the human body needs help with the absorption of calcium from the intestines, and a wide range of other minerals and vitamins are needed in this regard. The most common and arguably the most important of these is Vitamin D, which is essential to ensure that dietary calcium can be properly absorbed.
Best Dietary Sources of Calcium
Dairy products are a major source of calcium, and milk, yoghurt and cheese all contain high levels of this element. However calcium is present in a wide range of foods, and many common foodstuffs are fortified with calcium to help ensure an adequate daily intake. Vegans who do not eat dairy products and the lactose intolerant need to get calcium from non dairy sources, although lactose free dairy products are now widely available. Interestingly, the calcium content of dairy products varies with the level of fat that they contain, and the general rule is that the higher the fat content the lower the calcium content will be. This will be of particular interest to anyone trying to watch their weight.
Some of the best sources of dietary calcium include the following:
- Milk, yoghurt & cheese
- Oily fish, especially sardines
- Leafy vegetables such as pak choi, bok choi, cabbage & turnip greens
- Broccoli & Kale
The following products can contain high calcium levels as they are often fortified with this mineral; however you should check the packet for information on the specific brand or product.
- Breakfast cereals
- Soy products
- Orange juice
- White bread
Recommended Dietary Allowance (RDA) of Calcium
The recommended daily intake of calcium varies with age. It is essential that children have sufficient levels of calcium to ensure the bones grow strong and healthy, but all adults need to ensure that calcium intake is kept high to ensure the bones can be properly maintained. Infants under 6 months require 200 mg per day, from 7-12 months the RDA is 260 and 700 mg per day between years 1 and 3.
From the age of 9 children need to have a daily intake of at least 1300 mg per day, dropping to 1000 mg a day from the age of 18 to 50, with 1200 mgs per day recommended for the over 50s.
Magnesium and Bone Health
Magnesium is plentiful in the body and is in greatest concentration in the bones with about half of your body’s magnesium stored in the bones. It is the second most abundant mineral in bone behind calcium. While it is essential that this mineral is consumed while the bones are forming, it is also vital for the maintenance of healthy and strong bones. As with calcium which has numerous roles in the body, the same is true for magnesium. Magnesium also has an important role in cellular function and the maintenance of the nerves, in addition to helping with immune system function, blood sugar and pressure maintenance and the formation of proteins. Magnesium is also involved in the regulation of calcium levels, and helps with the absorption of calcium from the intestines. If magnesium levels are low this will affect calcium uptake. Magnesium has also been shown to stabilize the turnover of bone, and it is important for the maintenance of a healthy bone denisty¹ and this has important implications in the prevention of osteoporosis.
Magnesium also helps with the regulation of hormones which stimulate the breakdown of bone, can promote the release of enzymes which help with ossification (bone formation). Magnesium is also believed to be involved in the conversion of vitamin D to its active form, which in turn is essential for the absorption of calcium in the intestines. Should magnesium levels fall, the impact on bones can be significant. Rather worrying is the fact that according to one study², low magnesium levels are very common in the elderly and in women in particular.
Best Dietary Sources of Magnesium
A healthy and balanced diet containing plenty of green vegetables, nuts and grains will ensure that sufficient quantities of magnesium are ingested on a daily basis, although due to the importance of this element and the fact that excess magnesium can easily be excreted from the kidneys, taking magnesium supplements can be highly beneficial especially for those suffering from osteoporosis. Wheat bran is particularly high in magnesium, as is spinach and nuts such as almonds and cashews contain high magnesium levels. All legumes have good quantities of magnesium, as do all green leafy vegetables as magnesium is present in chlorophyll.
Recommended Dietary Allowance (RDA) of Magnesium
Even though magnesium deficiency is relatively rare – or at least to the point where symptoms of a deficiency are displayed – it has been suggested that many Americans do not consume their RDA on a daily basis. The RDA of magnesium in adults is 420 mg per day for males over 31 and 320 mg per day for women over 31. Between 14 and 18, women need more magnesium than adults, with 360mg per day recommended dropping down to 310 mg in early adulthood. For boys, the level required remains fairly constant with 410 mg per day recommended between 14 and 18, dropping to 400 mg per day for young adults.
Phosphorus and Bone Health
Phosphorus is another major structural element in the bones and the teeth, with this element accounting for approximately 1 percent of your total body weight. 85 percent of your body’s phosphorus is present in your bones. While a deficiency of phosphorous is bad for bone health and can cause bone pain, the chances of developing a phosphate deficiency is very low. What is more of a worry however is when the phosphorus intake is too high. Concerns have been raised in recent years about the high quantities of phosphate in fizzy drinks³. Many fizzy drinks contain phosphoric acid, which is believed to be bad for the health if excessive quantities are consumed.
Phosphorus is easily absorbed into the blood via the small intestine but should be excreted by the kidneys in consumed in excess. However high blood phosphate levels may reduce the levels of calcium in the blood, and it is believed to inhibit the production of calcitrol (the active form of Vitamin D) in the kidneys. It can also increase the release of certain hormones which are involved in the breakdown of bone.
High phosphorus intake may be more of a concern if insufficient levels of calcium are being consumed, due to the its effect (in excess) on calcium absorption. While the level of phosphorus in the diet has not been shown to cause a decrease in bone density in humans, some evidence exists to show that this is the case in dogs which have been fed a high phosphorus and low calcium diet⁴. The role of phosphorus and the prevention of osteoporosis has yet to be fully defined, and further research is needed to determine if this important mineral can help in the treatment or prevention of this disease when taken as supplements.
Best Dietary Sources of Phosphorus
Phosphorus is present in high quantities in meat, eggs, fish, dairy products, grains and also in carbonated drinks, although the latter as previously stated may be a cause for concern. It is very rare for phosphorus levels to fall to dangerous levels in healthy individuals even with a relatively poor diet; however some health conditions can affect how this element is absorbed. Sufferers of celiac disease (gluten intolerance) and Crohn’s disease may have a reduced ability to absorb dietary phosphorus, and the long term use of water pills and antacids may also similarly affect phosphorus levels in the body. The RDA of phosphorus for adults is 700 mg per day.
Multivitamins and Mineral Supplements
The best way to ensure you have sufficient levels of calcium, magnesium and other important trace elements is to eat a varied diet including the foodstuffs mentioned above. However mineral supplements can be highly beneficial, especially for supplementing the daily intake of calcium and magnesium in later life. Both of these minerals are strongly linked to the prevention of osteoporosis and osteopenia, and taking dietary supplements may well stave off the onset of both of these bone thinning conditions.
NIH Osteoporosis and Related Bone Diseases ~ National Resource Center
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Office of Dietary Supplements
Centers for Disease Control and Prevention
- ¹Magnesium supplements stabilize bone turnover (J Clin Endocrinol Metab 1998;83:2742-8) and helped support optimal bone density in a controlled clinical trial (Magnesium Res 1993;6:155-63)
- ² Low magnesium intake is common among women and the elderly (Magnes Res 1992;5:61-7; J Am Coll Nutr 1999;18:406S-412S)
- ³Calvo MS, Park YK. Changing phosphorus content of the U.S. diet: potential for adverse effects on bone. J Nutr. 1996;126(4 Suppl):1168S-1180S
- ⁴The effects of high phosphorus intake on calcium homeostasis. Calvo ms, Adv Nutr Res. 1994;9:183-207