Articles

Humans have a long tradition of holding genes responsible for individual differences in behavior (of course, we called it "blood", then, or "family"). In the 20th century, a counter-belief arose: that it was all down to environment, to upbringing. In more recent decades, we have become increasingly aware of how tightly and complexly genes and environment are entwined.

Let me start by saying that if you're healthy and are eating a good balanced diet, there should be no need for you to take supplements. I also want to emphasize that the best way of meeting your body's needs for certain vitamins and minerals is to get them from food. In some cases, for one reason or another, this may not be possible. For example, as a (mostly) vegan, I take iron and B12 supplements, to make up for these deficiencies in my diet. Elderly adults with small appetites may also find it hard to get all the nutrients they need from their diet.

Prevalence of dementia

Dementia is estimated¹ to afflict over 35.5 million people worldwide -- this includes nearly 10 million people in Europe, nearly 4.4 million in North America, nearly 7 million in South and Southeast Asia, about 5.5 million in China and East Asia and about 3 million in Latin America.

Here are some notes on the water cycle:

There have been quite a few studies looking into the possible benefits of omega-3 fatty acids and fish (a good source of the oils), particularly for older adults. Several large studies have found that regular intake of oily fish is associated with lower rates of dementia, and some evidence that eating fish regularly slows the rate of 'normal' age-related cognitive decline.

A very common situation today, which is probably responsible for a great deal of modern anxiety about failing memory, is that where we're required to “multitask”, that trendy modern word for trying to do more than one thing at a time. It is a situation for which both the normal consequences of aging and low working memory capacity has serious implications.

Prevalence

Vascular dementia, as its name suggests, is caused by poor blood flow, produced by a single, localized stroke, or series of strokes.

It is the second most common dementia, accounting for perhaps 17% of dementias. It also co-occurs with Alzheimer's in 25-45% of cases. Although there are other types of dementia that also co-occur with Alzheimer's, mixed dementia generally refers to the co-occurrence of Alzheimer's and vascular dementia.

The limitations of working memory have implications for all of us. The challenges that come from having a low working memory capacity are not only relevant for particular individuals, but also for almost all of us at some points of our lives. Because working memory capacity has a natural cycle — in childhood it grows with age; in old age it begins to shrink. So the problems that come with a low working memory capacity, and strategies for dealing with it, are ones that all of us need to be aware of.

Brain tissue is divided into two types: gray matter and white matter. These names derive very simply from their appearance to the naked eye. Gray matter is made up of the cell bodies of nerve cells. White matter is made up of the long filaments that extend from the cell bodies - the "telephone wires" of the neuronal network, transmitting the electrical signals that carry the messages between neurons.

The volume of gray matter tissue - a measure you will see cited in various reports - is a measure of the density of brain cells in a particular region.

Consider our facts about blood:

• arteries are thick and elastic and carry blood that is rich in oxygen from the heart.
• veins are thinner, less elastic, and carry blood rich in carbon dioxide back to the heart.

We could, as is often advised, simply turn these into why questions. And we can answer these on the basis of the connections we’ve already made:

Why are arteries elastic?

Because they need to accommodate changes in pressure

Why are arteries thick?

Because they need to accommodate high pressure