Osteoporosis, a leading cause of bone fractures, is the most widespread degenerative disease in the West, affecting around three million people in the UK and 10 million in the US. Women are most at risk, with one in six Western women expected to suffer a hip fracture at some point in their lives.
Our genes, age, diet and lifestyle are all known to have an influence on our bone health. Now, it appears that our mental health may also have a significant part to play.
Indeed, intriguing new research has found that depression, a condition that afflicts more than 120 million people worldwide, could be an important risk factor for osteoporosis-and especially in women.
The brain-bone link
Two recent meta-analyses-pooling the results of several previous studies-have found a clear connection between depression and low bone mineral density (BMD), an indicator of osteoporosis and fracture risk. The latest, an international study carried out by scientists at the Hebrew University of Jerusalem, assessed data from 23 research projects in eight countries, comparing bone density in 2327 people suffering from depression with that of 21,141 non-depressed individuals.
The researchers found that the depressed had substan-tially lower BMD than the non-depressed, and that depression was also associated with markedly greater activity of osteoclasts, the cells that break down bone.
What's more, the connection between depression and bone loss was particularly strong in premenopausal women with clinical depression diagnosed by a psychiatrist.
The scientists concluded that "all individuals psychi-atrically diagnosed with major depression are at risk for developing osteoporosis, with depressed young women showing the highest risk" (Biol Psychiatry, 2009; 66: 423-32).
The other meta-analysis came to much the same conclusion. On reviewing data from more than 10,000 people from 14 separate studies, US researchers from the Mayo Clinic in Arizona reported that depression was associated with a significant decrease in BMD of the spine and hip, especially in depressed women and in those with clinical depression. "Depression should be considered as an important risk factor for osteoporosis," the researchers concluded (Osteoporos Int, 2009; 20: 1309-20).
So, is depression the cause of the bone loss or does some other factor explain this novel link?
According to one study, it may not be depression per se that's the problem, but the drugs used to treat it. In 5000 people aged 50 years and over, Canadian researchers found that those regularly taking the antidepressants known as 'selective serotonin-reuptake inhibitors', or SSRIs, had a twofold increased risk of bone fractures. SSRI use was also dose-dependently associated with greater odds of falling, and lower BMD of the hip and spine (Arch Intern Med, 2007; 167: 188-94). A review of the scientific literature reached a similar conclusion (Eur Neuropsychopharmacol, 2009; 19: 683-92).
Nevertheless, there's also evidence that depression itself could be causing bone loss. Hebrew University of Jerusalem researchers have found that depression sets off the sympathetic nervous system-connecting the brain to the internal organs and skeleton-which is primarily aroused by stress. Its activation causes secretion within the bone of 'noradrenaline' ('norepinephrine'), which has a detrimental effect on bone-building cells. The Israeli researchers were able to show that chronic treatment with a drug that blocked noradrenaline in the bone also blocked the effects of depression on bone (Proc Natl Acad Sci USA, 2006; 103: 16876-81; Ann NY Acad Sci, 2010; 1192: 170-5).
Although more studies are needed in this field-dubbed 'neuro-psycho-osteology'-some scientists are already call-ing for depression to be officially recognized as a risk factor for osteoporosis. Indeed, the findings suggest that dealing with depression may be an important means of keeping bones strong and preventing fractures (see WDDTY vol 18 no 12, or www.wddty.com/how-you-beat/depression, for more information on how to treat depression naturally).
Other risk factors
Besides depression, other factors can increase the risk of osteoporosis. Some, such as being female, getting older and having a family history of the condition, can't be changed. But there are other things we can do something about.
o Sedentary lifestyle. People who spend a lot of time sitting are more likely to develop osteoporosis. As Marilyn Glenville explains in The Natural Health Bible for Women (Duncan Baird, 2010), bone strength depends on supply and demand. "If you demand lots from it, it will supply the bone density to accommodate your demands; if you make few demands on it, your bone density will reduce proportionately."
Studies show that regular weight-bearing exercise is important for building and maintaining bone strength. Low-impact activities such as walking and gentle aerobics can prevent bone loss, while high-impact exercise like running and weight-training can increase bone density (Postgrad Med J, 2003; 79: 320-3). Football is a helpful activity. A 14-week study of women, aged 20-47 years, who played football twice a week showed significantly increased bone density in the shins. Surprisingly, similar female runners who trained for the same amount of time didn't see such dramatic effects (Scand J Med Sci Sports, 2010; Mar 4; Epub ahead of print).
For the less mobile, whole-body vibration training (WBVT), which involves standing, sitting or lying on a vibrating platform to stimulate muscle contractions, is a good option. Postmenopausal women having WBVT three times a week for six months saw significant increases in hip BMD, as well as in strength and balance (J Bone Miner Res, 2004; 19: 352-9). WBVT also prevented bone loss in the spine and femur (thigh bone) compared with a placebo (J Bone Miner Res, 2004; 19: 343-51).
If you already have osteoporosis, exercise that improves balance and coordination, such as Tai Chi or step aerobics, can help to prevent falls and fractures (BMC Geriatr, 2006; 6: 6).
o Acidic diet. While some foods supply us with essential bone-building nutrients such as calcium, others can be detrimental to bone health. Says Annemarie Colbin, author of The Whole-Food Guide to Strong Bones: A Holistic Approach (Oakland, CA: New Harbinger Publications, 2009), watch out for acid-forming foods-such as meat and sugar-as excess intakes drain calcium and other minerals from the bones. Studies in mice show that acidosis-a tilt towards an acidic blood pH-encourages bone loss and inhibits bone formation (Curr Opin Nephrol Hypertens, 2004; 13: 423-36). This may explain why older women who eat chocolate (high in sugar) every day have less bone density and strength (Am J Clin Nutr, 2008; 87: 175-80), and why certain drinks are linked to osteoporosis (see below).
The best diet for better bones includes acid-forming and alkalizing foods such as leafy green vegetables (kale, collard and mustard greens, watercress, arugula), roots (carrots, turnips, parsnips, radishes), broccoli and squash (for more information, see WDDTY vol 19 no 12).
o Coffee and alcohol. Caffeine increases urinary loss of calcium and magnesium (J Nutr, 1993; 123: 1611-4), and four or more cups of coffee a day is linked to a higher risk of fractures, particularly in women with low calcium intakes (Osteoporos Int, 2006; 17: 1055-64). In contrast, tea appears to be bone-protective (Am J Clin Nutr, 2007; 86: 1243-7), as it contains other healthful ingredients such as flavonoids.
Heavy alcohol consumption is also implicated in osteoporosis (Alcohol Clin Exp Res, 2010; Feb 24; Epub ahead of print), but a moderate consumption (1-2 drinks/day) may be beneficial to bone in men and in postmenopausal women (Am J Clin Nutr, 2009; 89: 1188-96).
o Smoking. Cigarettes are a known risk factor for low BMD and osteoporo-sis (J Cross Cult Gerontol, 2005; 20: 109-25). Smoking more than a pack a day is associated with a 60-per-cent greater risk of osteoporosis (Bone, 2010; Mar 31; Epublication ahead of print). Also, Japanese researchers have discovered changes such as fewer marrow cells and osteo-blasts (bone-making cells) in the bones of smoke-exposed rats. Although these findings may not apply to humans, they suggest that even passive smoking may adversely affect bones (Orthopedics, 2010; 33: 90-5).
o Changes in weight. Studies have shown that those who have successfully lost weight also had greater bone loss compared with those who didn't lose weight (J Clin Endocrinol Metab, 2007; 92: 3809-15). So, if you're on a weight-loss diet, be sure to increase your physical activity (preferably with high-impact exercise) and ensure that your intake of bone-building nutrients is adequate (see box, page 19).
o Certain medications. Long-term use of corticosteroid medications such as prednisone and cortisone can lead to osteoporosis (Presse Med, 2006; 35: 1571-7). Other drugs that have been linked to brittle bones include aromatase inhibitors, used to treat breast cancer (Bratisl Lek Listy, 2010; 111: 27-32), and acid-blocking proton pump inhibitors (Curr Gastroenterol Rep, 2010; Apr 24; Epublication ahead of print).
Prevention is the key
Ultimately, as osteoporosis is a 'silent' condition-it's usually asymptomatic until a bone fracture occurs-under-standing what causes it is our best weapon against it. Indeed, research suggests that making simple changes to our diet and lifestyle now can have
a big impact on our bones for years to come.
WDDTY VOL 21 NO 3