Nutrition Connection: Healthy Bones • Spring 2007
When it comes to bone health and warding off osteoporosis, one nutrient that comes to mind is calcium. Another is vitamin D. Yet another we should be aware of, say researchers from Penn State University, is a type of omega-3 fatty acid called alpha linolenic acid.
To understand the effects of this fatty acid, first consider bone metabolism. Although we think of bones as something solid and static, that’s not actually true. Behind the scenes, bones have an ongoing breakdown of bone tissue and buildup of new tissue. Breakdown and buildup each occur at their own rates. Osteoporosis develops as there is more breakdown than buildup, and the bones lose some of their mineral deposits (calcium and phosphate). This makes them less sturdy, and more prone to fracture—a process that occurs gradually, over many years.
The Penn State research introduced walnuts into the diets of participants, mainly through walnut granola, walnut pesto, and similar products. Walnuts are extremely rich in alpha linolenic acid. The results suggest that this fatty acid does two things:
1 – Reduces bone turnover
2 – Tips the scales so that there is more buildup than breakdown.
This is one of many studies focusing on alpha linolenic acid, which is now thought to decrease heart disease risk, help prevent insulin resistance characteristic of Type 2 diabetes, improve memory and brain functioning, and reduce inflammation throughout the body. Food sources of alpha linolenic acid also include flaxseed, soybeans, tofu, soybean oil, and canola oil.
“Beefing Up” Vitamin D Intake
Another area of discovery in nutrition relates to vitamin D, a fat soluble vitamin that helps the body use calcium, improves physical strength of the elderly, helps prevent falls and fractures, and may also help prevent or control Type 2 diabetes.
According to researchers, the dilemma with this powerful vitamin has been concern for toxicity, such as elevated blood calcium levels leading to kidney stones. Intake recommendations are set by the Food and Nutrition Board, and suggest a safe Upper Limit (UL) of 2000 IU. New review and analysis this year by four researchers led to a conclusion that five times this daily dosage – 10,000 IU or 250 micrograms per day – would be safe, and may offer health benefits for most healthy adults. Vitamin D reaches us through diet, especially vitamin-D fortified foods, through supplements, and through exposure to sunshine, which helps the body produce its own vitamin D. Some research is showing that vitamin D deficiency is more widespread than we might have imagined.
This dietary mineral receives a lot of attention with regard to osteoporosis, and rightly so. Surveys suggest that the majority of people simply don’t consume enough calcium—60% of men and 90% of women. For adults aged 51+, the goal is at least 1200 mg per day, or the equivalent of four 8-oz glasses of milk. Intake of magnesium and phosphorous is also important. Foods high in calcium and phosphorous worth emphasizing in a healthy diet include milk and dairy products, dark green leafy vegetables, broccoli, and canned sardines or salmon. Many food products are also fortified with calcium—from soy milk to orange juice to cereals, to name a few.
Along with calcium, dark green vegetables also provide magnesium. Nuts, seeds, and legumes also provide magnesium.
Caffeine and Soda Pop
Another dietary factor that affects bone density is caffeine, as in coffee. One study examining elderly women found that three cups of coffee per day led to bone loss in the spine. Experts suggest limiting coffee intake, especially among the elderly. Caffeine causes some calcium loss, and aging bodies may not be able to compensate for this effect.
In the beverage department, another product of concern is soda pop. Besides the caffeine in some soda pop products, there’s another concern. Researchers say that even among young people, the fructose sweetener in soda pops upsets bone metabolism, leading to mineral loss. In all, a glass of milk may be a healthier choice.
One study after another has demonstrated the impact of exercise on bone density. Beginning early in life, a habit of regular exercise promotes strong bones. Much of the advice has focused on weight-bearing exercises, such as walking, running, stair-climbing, dancing, or playing tennis. Extended research now demonstrates that any form of exercise promotes bone health. For example, resistance exercises, swimming, and stationary bicycles are of value as well. Along with diet, exercise plays a critical role in maintaining bone density.
National Institutes of
Health – Osteoporosis: http://nihseniorhealth.gov/
National Osteoporosis Foundation: www.nof.org
USDA Nutrient Database
List of high-calcium foods: www.nal.usda.gov/fnic/foodcomp/
List of high-magnesium foods: www.nal.usda.gov/fnic/foodcomp/
List of high-phosphorous foods: www.nal.usda.gov/fnic/foodcomp/
Not to be underestimated, osteoporosis affects at least 10 million people in the US, and leads to 1.5 million fractures every year. Women, particularly those who have passed menopause, are highly susceptible to mineral loss from the bones. Experts estimate that 20% of women over age 50 have some osteoporosis, and another 30% have low bone density. As testosterone levels decline, men also have a risk for osteoporosis. For every man with osteoporosis, there are eight women who have it too.
It’s not unusual for a person to be unaware of this “thinning” of bones until a fracture occurs, and experts suggest about half of all women over age 50 will experience a fracture of the hip, vertebrae in the spine, or wrist. Some people call osteoporosis a silent disease, because it develops over decades, with no symptoms. According to the National Institutes of Health, hip fracture and impairment of walking are key reasons individuals enter nursing homes.
A dietary manager can help raise awareness of key prevention factors for osteoporosis. Because osteoporosis reflects a dynamic state of bone density, the situation can be improved through a range of interventions that include diet, exercise, and sometimes supplements and medications. From a dietary perspective, a focus on foods rich in calcium, vitamin D, phosphorous, magnesium, and alpha linolenic acid is well-justified. A dietary manager can also discourage excesses of coffee, soda pop, and alcohol to help promote health bones.
By Sue Grossbauer