LOS ANGELES - MO - Eating too much red meat could increase the risk of Alzheimer’s, suggests new research.
Scientists found that a build-up of iron - abundant in red meat - could cause oxidant damage, to which the brain is particularly vulnerable.
Researchers say this could in turn increase the risk of Alzheimer’s.
Professor George Bartzokis, of UCLA in the United States, said that more studies have suggested the disease is caused by one of two proteins, one called tau, the other beta-amyloid.
As we age, most scientists say, these proteins either disrupt signaling between neurons or simply kill them.
He and colleagues looked at two areas of the brain in patients with Alzheimer’s and they compared the hippocampus, which is known to be damaged early in the disease, and the thalamus, an area that is generally not affected until the late stages.
Using brain-imaging techniques, they found that iron is increased in the hippocampus and is associated with tissue damage in that area. But increased iron was not found in the thalamus.
Professor Bartzokis said that most research had focused on the build up of the proteins tau or beta-amyloid that cause the plaques associated with the disease.
But he believes the breakdown occurs further ‘upstream’, and it is the protein’s destruction of myelin, the fatty tissue which enables nerve signals to be sent along fibres, which disrupts communication and promotes the build-up of the plaques. These amyloid plaques in turn destroy more and more myelin, disrupting brain signaling and leading to cell death and the classic clinical signs of Alzheimer’s.
He points out that myelin is produced by cells called oligodendrocytes.
These cells, along with myelin itself, have the highest levels of iron of any cells in the brain, Bartzokis says.
He adds that although iron is essential for cell function, too much of it can promote oxidative damage, to which the brain is especially vulnerable.
Hypothesising that elevated iron in the tissues could cause tissue breakdown, he targeted the vulnerable hippocampus, a key area of the brain involved in the formation of memories, and compared it to the thalamus, which is relatively spared by Alzheimer’s until the very late stages of disease.  They found increased iron levels in patients with Alzheimer’s.
Prof Bartzokis said: ‘It is difficult to measure iron in tissue when the tissue is already damaged.’ But the MRI technology we used in this study allowed us to determine that the increase in iron is occurring together with the tissue damage.
‘We found that the amount of iron is increased in the hippocampus and is associated with tissue damage in patients with Alzheimer’s but not in the healthy older individuals - or in the thalamus.
‘So the results suggest that iron accumulation may indeed contribute to the cause of Alzheimer’s disease.’
The link to iron could mean that dietary changes and surgical interventions could lower the chances of the developing the disease, he said. He explained: ‘The accumulation of iron in the brain may be influenced by modifying environmental factors, such as how much red meat and iron dietary supplements we consume and, in women, having hysterectomies before menopause.’