Tuesday, 27 January 2015

potassium salts and osteoporosis

Last week on Woman's Hour (19/01/15) Dr Helen Lambert came on the show to tell us about her research into osteoporosis. As Helen explained, osteoporosis causes 1 in 2 women and 1 in 5 men to get a fracture due to poor bone health over the age of 50. She says studies show us that we can significantly reduce osteoporosis by having more potassium salts (potassium bicarbonate and potassium citrate) in our diet. These are found in fruit and vegetables.

For some reason they also had GP Clare Gerada on the show. She was quite dismissive of the importance of Dr Lambert's work. She seems to have accepted the ideas of Gyorgy Scrinis and Michael Pollan. They believe that there is something they call 'nutritionism', which they oppose. Nutritionism is when individual nutrients such as vitamins and minerals are examined in isolation from other nutrients in normal food and said to be healthy or unhealthy. This is what Clare Gerada said.

"So I think the important thing for all of us is to demedicalize all of this, in other words take doctors out of the equation, take the health professionals out of the equation and start to look at inviduals in society and why we're not doing things that our grandmothers knew we should be doing, eat and apple a day, walk a little bit, get exposed to sunshine and I think (and Helen's research sounds fantastic) but I think we've got (in a way) to start giving some simple messages not from doctors not from nurses ..."

In saying "we've got to start giving some simple messages not from doctors" Clare Gerada is saying that no one should pay any attention to this research. This shows the danger of talk about nutritionism. People can use the research to reduce the amount of discomfort in their lives. Not live in pain like 'our grandmothers' did. Dr Lambert suggests we eat more fruit and vegetables, but even that suggestion is dismissed by Dr Gerada. She said something like 'Do I want to eat 10 bananas a day?'.

The research is another reason why we should eat more fruit and vegetables. Potassium salts found in fruit and vegetables make our bodies slightly more alkaline. That has an effect on bone health but it probably has an effect on other aspects of health too. It's not just potassium salts that do this though, calcium, magnesium and sodium salts do too. I take calcium citrate and magnesium citrate in a tablet. I know Clare Gerada and Michael Pollan wouldn't approve of this, but I think I am being sensible in doing it.

Last year Michael Pollan gave a lecture on BBC Radio 4's Analysis (03/09/14). As well as his ideas about fat and carbohydrate (he seems to believe that all fats are good and all carbohydrates are bad) and his ideas about poverty (poor people are unhealthy because they have to eat cheap unhealthy processed foods) he talked about individual nutrients in general and beta-carotene in particular.

He said that someone had done some research where smokers were given beta-carotene to see what effect it had on their health. Beta-carotene is used by the body to make vitamin A which is an antioxidant. People expected it to decrease the incidence of cancer. The test was suspended when the beta-carotene group started developing cancer at higher rates than the control group. Pollan's analysis of this is that any individual nutrient by itself will act differently from when it occurs in nature and in food.

This is at best a generalization. It could be true of some nutrients. We don't know why smokers who took beta-carotene got higher levels of cancer. Part of the reason could be the large amount taken. Another reason could be that the body can use oxidants to tackle cancerous cells, and so anybody who has an increased risk of cancer shouldn't have high levels of antioxidants (whether they come from tablets or from a diet high fruit and vegetables). This is the antioxidant paradox, but it only applies to people who have a higher than usual risk of cancer, and it can't be used to suggest that single nutrients are of no value.

I also take a vitamin D tablet each day, because there is now a lot of research to show that vitamin D in significantly higher levels than can be achieved through diet or exposure to sunlight has an important role in human health. I don't take a mega dose of vitamin D or anything else. Pollan wouldn't agree with this, just as he wouldn't agree with me getting most of my calories from long-grain rice and pasta (cheaper than any processed food, cheaper than sugar in terms of cost of calories). But the evidence is that my bone health will be better than his in old age. He might want to end up like his grandmother but I don't.

I also have a healthy diet with lots of fruit and vegetables, and little fat, sugar or salt. One of the messages of people like Pollan and Gerada is that people get confused over health messages. However, the simple message for a long time has been eat less fat, sugar and salt, and more fruit and vegetables. I don't eat as much protein as most British people, because I know people overestimate the amount of protein they need but also protein is one of the foods that tends to make the body slightly more acidic.

If you believe Michael Pollan you will believe
  1. if you're poor, don't even bother to try and eat healthy food because you won't be able to
  2. you can eat at any amount of any type of fat that you want
  3. you should avoid carbohydrate, don't distinguish between sugars and starches, or low GI starches and high GI ones
  4. don't take a multivitamin and multimineral tablet each day, and don't take vitamin D or calcium citrate because they can't do you any good and may do you harm
I think he's wrong about all of these things, and that will have an effect on the future health of anyone who pays attention to him.

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