Everywhere I look in medicine these days, I am seeing improbable connections.
In our cover story this month, we've discovered that macular degeneration tends to be present in people with heart problems, such as high cholesterol, hypertension and atherosclerosis. It also develops in many patients with diabetes. I then came across an article on osteoporosis. A group of researchers at Tufts University, Harvard and Boston University had enlisted 2000 men and women, aged between 59-91, from the Framingham Study, the well-known study which has mapped the degenerative diseases of some 5000 residents in the small town of Framingham, Massachusetts, over 50 years.
The researchers had taken blood samples from these people during 1979-1982 and measured total homocysteine levels. These participants were then followed from that time until June 1998, and the incidence of hip fracture recorded. Those initial homocysteine levels were then compared with the hip-fracture rates.
What the researchers discovered was that those with the highest levels of homocysteine in the blood had four times the risk of hip fracture (if men) and twice the risk (if women) compared with those with the lowest levels of homocysteine. Interestingly, being male was more a risk factor than being female. Similar results were found in a Dutch study (N Engl J Med, 2004; 350: 2033-41, 2042-9).
Homocysteine is an amino acid resulting from the normal breakdown of proteins in the body. It is converted into another amino acid called methionine. Excess levels of homocysteine in the blood are an indication that this complicated process isn't going as well as it should. It means quite simply that the body is drowning in protein.
Although the New England Journal of Medicine speculated that raised homocysteine levels could well just be an 'innocent bystander' to the development of osteoporosis, my own view is that this is the most crucial connection yet.
In the past, the Framingham study has determined a firm relationship between high levels of homocysteine and atherosclerosis and also stroke - the higher the level of homocysteine, the more narrowed the arteries (N Engl J Med, 1996; 332: 286-91).
It's now been well established that raised homocysteine levels result from deficiencies of the B vitamins - specifically, B6, B12 and folic acid. Heart-disease patients with high homocysteine levels improve dramatically with simple supplements of these vitamins; in one study, for instance, the risk of vascular disease was reduced by about two-thirds (Irish J Med Science, 1995; 164 [Suppl 15]: 51A).
Low levels of folic acid and B12 have been linked to bone mineral density (Bone, 2003; 33: 956-9). It is also well known that high levels of protein in the diet predispose to osteoporosis.
However, B vitamins aren't the entire story.
Other evidence shows that heart patients are also deficient in certain minerals, such as chromium and magnesium. All these nutrients - the B vitamins, chromium, magnesium - have one thing in common. They are all largely refined out of manufactured, high-sugar foods. Virtually any process that interferes with the natural state of a foodstuff - milling or canning grains, meats, fish and vegetables - will refine out up to three-quarters of B vitamins.
It may well be that osteoporosis, AMD and virtually all the major degenerative diseases of the West have only a single cause at their core. Everything leads back to processing and sugar. As E.M. Forster famously put it: 'Only connect'.