Ah, now I see!

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A Sydney doctor has been studying human retinas since 1976 and says the carrot myth, that eating carrots is good for your eyes, started in World War II, is a "complete fabrication". Dr Beaumont is the director of the Macular Degeneration (MD) Foundation.

"When the English ... were flying at night they used radar but the Germans didn't know that radar existed," Dr Beaumont said from his Sydney clinic. "The English certainly didn't want them to know so they put out a myth saying they were feeding their pilots carrots to improve their night vision and that's why they could fly and see things at night.

Dr Beaumont recommends eating lutein rich foods for eye health. The lutein (found in spinach, corn and egg yolks) helps protect the eye from sight-damaging light that causes MD and blindness, Dr Beaumont explains.

On the flipside, ironically, foods rich in beta carotene - like carrots - can damage the eye's protective shield, doubling your risk of contracting the disease.

So much for old wive's tales.

Related to that, there is at least one recorded case of a person dying from drinking excessive amounts of carrot juice.

While we need Vitamin A (beta carotene is a Vitamin A precursor), it is actually quite toxic.
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Prostate Cancer and Red Wine

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The Australian media was abuzz last week with a report that alcohol consumption increases the chances of prostate cancer. Two drinks a day will increase your risk by 20%. The risk increased with the number of drinks consumed in a day.

Before I pour my home brew down the drain, there are a few things I need answered.
(If you haven't read my previous post, now's a good time. I'll wait.)

Causality
Could alcohol consumption cause/increase the risk of prostate cancer? Possible.
Could prostate cancer risk cause drinking? Improbable.
Could a third factor be in play? Possible. Here are a few possible other factors:

People who drink large amounts of alcohol a day are often overweight. Is BMI a factor?
The consumption of chips, nuts and snack foods is probably proportional to drinks consumed.
Big drinkers often eat more meat.
Is consumption of other foods an issue - fibre, greens, fruit?
Do drinkers live longer, due to the heart benefits of alcohol, and get cancer due to longevity?

That will do. I'm sure we could come up with more. You can begin to see the difficulty of extracting two issues from a very complex life-matrix.

Crud Factor
Is a crud factor in play? Possibly. Sometimes a big survey like this finds statistical significance where no practical significance exists or will average out differences in reports.

Compare the following two extracts from studies into prostate cancer and alcohol consumption:

Our present study suggests that consumption of beer or liquor is not associated with prostate cancer. There may be, however, a reduced relative risk associated with increasing level of red wine consumption. Int. J. Cancer: 113, 133–140 (2005).

Wine or beer consumption was unassociated with prostate cancer; however, moderate liquor consumption was associated with a significant 61–67% increased risk of prostate cancer. International Journal of Epidemiology 2001;30:749-755

Looks as if beer is neutral, red wine gets a sort of a plus and spirits get a sort of a minus.

So does the report mean anything?

Too early to tell really but I will put a punt on the benefits of moderate alcohol consumption outweighing the possible down side.
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Of sharks and ice-creams...

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Really this post is about statistics but you wouldn't have come if I had said that.

The thing is that there are reports published everyday on every possible subject, many of them food and health linked. My next post, which prompted this pre-post, is on prostate cancer and red wine. I am doing this post separately as I think I will be referring to it time and time again.

Newspapers happily publish these 'shock-horror' health reports, edited, cherry-picked, sensationalised and often unverified.

Readers, knowing no better, accept them on face value.

To help me explain, let me now call on some sharks and ice-creams.

Sharks & Ice Creams - the pursuit of causality.
There has been shown to be a strong correlation between shark attacks and ice-cream consumption in Australia.

Does that mean eating ice-creams make you more prone to being eaten by a shark?

Does it mean that, having been attacked by a shark, you start craving dairy food?

Or could it possibly be that a third thing, maybe the season, is controlling both things?

Indeed it is the case that it is in summer that both shark attacks and ice-cream consumption increase.

Independently.

Causality is fundamental to interpreting any report. What caused what? Whenever you see a report in the papers linking two things, ask yourself the following three questions:

• Is A really causing B, as claimed?
• Could B actually be causing A?
• Could something else, C, be causing both A and B?

The Crud Factor
The crud factor in statistics is an acknowledgement that everything is correlated.

If I was to find the data for tin production in Bolivia for the last ten years and also find the number of deaths in bicycle accidents in Belgium over the same period and plot them on an X-Y graph there would almost certainly be a correlation between the two.

A chance correlation.

It may be negative, it may be positive, it may be big or small, but it is most unlikely to be zero.

That is why all scientific research needs to be replicated; scientists test the same hypothesis (that tin production in Bolivia is impacting on bicycle fatalities in Belgium) using different data. If they can replicate the results then their confidence in the hypothesis increases.

It is not uncommon for replicate testing to fail to reproduce the original work.

Sadly, journal editors are not as keen to publish a negative result as they are to publish a positive and interesting one and such work often never gets beyond the waste bin. And, should they publish an article negating previous work, news media are far less likely to run it because it is not "news" and not shocking enough.

Summary
So, if there is a news item showcasing some horror relationship between a food and health or even some wonder cure, be ready to ask yourself if the implied causality makes sense and could it just be a chance correlation.

There you go. That didn't hurt, did it?
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More on Yoghurt

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Laveviewer asked: I have two questions: Are homemade yogurt and ice-cream better for you than the commercial varieties? I'm thinking that if you make these products and use them within a week or two, you don't need to worry about preservatives.

Neither yoghurt nor icecream have preservative generally. If they do, it is usually from the flavourings. Sauces and fruit purees often have preservatives, notably sulphites and sorbic acid. The preservative are there to keep the flavourings from going off before being used.

Once a frozen product, like ice cream, is produced it has a considerable lifetime as freezing is a natural form of preservation.

Part of the benefit of yoghurt is its bacteria content, so in this type of product preservatives can be a problem in a different way. Yoghurt usually relies on it's acidity to inhibit stray bugs.

Both can be made at home, time and enthusiasm permitting. You also have a better input into possible flavours. I made a delicious grapefruit and honey sorbet last summer. You wont find that in the shops.

But are they better for you? Hard to say. Commercial icecream had a pile of stabilizers and emulsifiers, and often a bare minimum of fat, possibly not even dairy fat if they call it iced confection. But home made icecream can be made with eggs and cream, it is really a frozen custard - infinitely superior in flavour but moderation required!

Home made yoghurt is fine as long as you use proper care and sanitation for making it.
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The Silver Bullet School of Nutrition.

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This is a previous post from "A Curate's Egg" but one which rightly belongs here and, in part, answers Kris loves Chocolate's question about which food are the healthiest for us.


I am not a fan of the ‘silver bullet’ school of nutrition.

By silver bullet, I mean the belief that some foods that are super foods.

Granted, some plants will kill you. That does not automatically mean that, in an effort to maintain even-handedness in the universe, there are some plants out there that are designed to save you.

But people seem to like wonder foods. Every year we hear about some berry, root or leaf from some exotic location that the native people know about and it keeps them happy, healthy and fucking like a hamsters, until they die of sexually induced exhaustion well into old age.

Oddly, these wonder foods seem to be most often sold by some multi-level marketing crowd.

Always, my first question is always the same: If this product is so good, why aren’t the pharmaceutical firms growing it, refining it, and mass producing it? Quinine was an example of where that did happen.

The problem with some of these wonder foods is that they are not supposed to cure a specific (and hence measurable) illness, such as malaria, but are generalists. They will stop cancer, aging, heart disease or some other intangible thing. Yes, death rates are measurable but you must keep an eye on causality. What’s that? The Hellarwi tribe never got heart disease AND the ate the wacko berry every day. Great! Perhaps the fact that they spent the day running around on foot and didn’t have an ounce of fat on them played a part too.

And the small matter of crocodile induced mortality.

Mind you, the crocodiles who eat the Hellarwi live to a ripe old age.

If you drink $40 worth of exotic berry juice a day and never get cancer, how do you prove it was the berry’s doing?

Perhaps you just weren’t going to get cancer anyway.
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Beef Jerky

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Photo: beefjerky.com

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Don said "I did a post about making jerky - dried meat. Someone asked if adding something sweet, like honey, might make the jerky less tough. The reasoning was because the sugar content makes a cake "softer". I don't know about the cake but do you think the sweetener would make the jerky less tough? (Not that I care, we don't like sweet jerky and go through this stuff as fast as I make it.)"

In theory honey or corn syrup would keep the jerky more supple but I would find the sweetness off-putting. Glycerine (Glycerol) may also work and is not so sweet.

Probably the best solution is to not dry it as much.

I occasionally make my own jerky. I use a variant of a recipe I found on line called Cliff's Fantastic Jerky. I vary it by using crushed garlic and chopped onion rather than the powders.

Far too nice to make too often.
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Wine & Champagne

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Kris loves Chocolate wrote "When I drink (one glass, I am not talking getting tipsy here) wine, I get a horrible migraine. Once in awhile I can sip on white wine and be ok, but never red wine. I can drink Champagne though. Someone said I am allergic to the sulphates? No sulphates in Champagne?"

Most alcoholic drinks contain sulphites; it is added to stop fermentation, to kill off unwanted yeasts and generally as a sterilizer in the brewing process.

If the sulphites were the source of your migraines you would get it from wines other than red ones. And foods other than wine. Sulphites are probably the most ubiquitous preservative in our foods, often in levels far higher than found in wine. It is found in anything from dried fruit to manufactured meat. Some people do respond badly to sulphites but it is rare.

Possibly your response is to the histamines in red wine. These are absent (or low) in white wines. Taking an antihistamine tablet before consuming some red wine would tell you whether you are responding to histamines or not. Again, it is possible but rare.

Tannins are another possibility as red wine has more of them than white wine. The colour of red wine is extracted from the grape skins and tannin is also extracted in the process. If this was the case you would expect eating dark grapes would produce a headache. Even drinking tea may give a headache, though obviously different tannins are present in tea.

The short answer is that no one knows why some people get a headache from red wine.

Sorry.
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