Tuesday, September 15, 2015

Cheese & blood cholesterol

Many years ago I worked for the Heart Foundation and it was standard practice to tell anyone newly diagnosed with high blood cholesterol that they had eaten their last piece of cheese. For some I had taken away their reason to live. Between the sobs they would plead: “Just one last cheese toasty, please.” I just had to shake my head and call for the onsite counsellor.

Now there is review article suggesting that I have been the cause of much undue concern.
Beyond saturated fat
The human creation of cheese was a very clever way to concentrate milk and increase it’s shelf life, making it a reliable food source. The enduring problem was its relatively high salt and saturated fat content, a combination that would raise both blood pressure and blood cholesterol. Dutch researchers have now looked at all the randomised control trials, most with a crossover design, comparing cheese and other foods such as butter, milk and tofu.

The authors say: “The results consistently showed that that the effects of cheese on lipids and lipoproteins were different than expected from the fat content.” What they are saying is, although cheese is high in saturated fat it didn’t raise cholesterol as predicted. Why? The abundant calcium in cheese could be binding with fats to reduce their absorption. Previous studies have observed that dairy calcium minimises a rise in blood cholesterol. The phospholipids in cheese may also be attenuating any rise in blood cholesterol.

Hard or soft?
As far as I can gather, the research was done primarily on hard cheese, such as cheddar. There wasn’t a study on soft cheeses like camembert. I suspect that soft cheeses would also have little effect on blood cholesterol, although that suspicion may be biased due to my absolute delight in enjoying an excellent brie or camembert.

What does it all mean?
In nutrition there are many questions. It would be perfect if we could say cheese is good or bad for the heart. It depends. Even now the Heart Foundation is not a big fan of full cream dairy products. They tell us to cut them out and replace them with reduced-fat or low-fat versions. Let’s be honest, reduced-fat cheese is dreadful, akin to eating the soft plastic casings for mobile phones.

So do this. Buy cheese. Buy really nice cheese. Like triple cream camembert. Enjoy it. Just don’t eat too much.

Dairy & heart disease: a lower risk than previously thought

It has been clear for a long time that not all saturated fats act the same. Saturated fats come in a range of lengths, dictated by the number of carbon atoms in the fatty acid chain. Look, it’s a chemistry thing, and 93% of people never did chemistry at school, let alone university. You can go to everyone’s friend Wikipedia if you want a quick refresher on saturated fat. Better still, just keep reading the next paragraph.

Let me just say, there is mounting evidence that dairy foods aren’t the evil forerunner to a life of wheezing or chest pain or drop dead heart attacks. In sensible amounts, milk, cheese and yogurt are a pretty good source of calcium, riboflavin and protein. The authors of one review paper regarding dairy and the risk of heart disease say they “could find no consistent evidence that dairy food consumption is associated with a higher risk of coronary heart disease.” There are many reasons why no clear link was seen in the studies:
  1. Great variation in the study designs
  2. Insufficient consideration of other lifestyle factors associated with heart disease
  3. More low-fat dairy foods became available over the last 40 years making it difficult to compare a study from the 1970s to one in the 2000s
  4. Often there was no distinction between high-fat and low-fat dairy products
Welcome to the world in which I live, where nutrition is not as simple as we would like, and our advice will vary from person to person. Look, I drink skim milk and eat good cheese. A contradiction? A bet each way? Or is it fine because I eat loads of fruit, vegetables, legumes, mushrooms and wholegrains? Whatever, I’m happy.

A2 milk
More recently there has been debate about the type of protein in milk and its influence on health. Milk with A1 beta-casein protein may cause more gut pain and looser stools than milk that exclusively contains A2 beta-casein. In fact, if someone has a milk intolerance then lactose may not be culprit, but A2 casein.

There is now a recent review that anyone can download. It is still early days in research terms, although the authors believe they have a compelling case for all dairy cattle to be the type that produce only A2 milk.

Saturday, August 15, 2015

Nutrition can be quite simple, given a chance

One favourite way of getting an answer to a nutrition and health question is to gather all the most recent published studies, put them in a data melting pot, and see if you can extract a “truth”. One review did this recently and found pretty much what you might expect, depending on your personal nutrition mantra or affiliation. They compared various foods groups and types to the risk of common diet-related disease such as heart disease, cancers, gut disease, bone and organ diseases and even mental illness.

Very simply put, they found that:
  1. Drinking tea may reduce the risk of type 2 diabetes, heart disease, Parkinson’s disease and some cancers eg breast and stomach cancer.
  2. Coffee drinking wasn’t quite as powerful as tea, yet seemed to drop the risk of type 2 diabetes, mental illness, heart disease and colon cancer.
  3. Milk pretty well had a neutral effect on long-term health, although it did a good job on maintaining good bone density
  4. Wine helped lower the risk of heart disease and many cancers (yoo-hoo!), but there was a warning: every glass bumped up the chance of getting breast cancer by 5%. Usual message – respect alcohol.
  5. Sweetened drinks increased the chance of overweight and diabetes, but only when consumed in unhealthy amounts.
  6. Fruit and veg, as expected, are wonderful for your health, especially for heart disease and cancer, as well as helping keep your weight in check.
  7. Wholegrains look good on all fronts, but white rice was associated with an increase in type 2 diabetes risk. The authors say that wholegrains are more health protective than fruit and veg.
  8. Legumes are another food that looks great for health, especially with a lower risk of most cancers.
  9. Nuts and seeds are great for keeping heart disease away, with nut lovers at 37% lower risk of heart problems. I guess they mean the unsalted type.
  10. Meat never seems to get good press, but the negatives are usually associated with a high consumption of red meat (see my comment below).

Any food over-consumed, be it meat, soft drink/sodas, wine or coffee, will always be associated with poor health, because if you over-eat something you are likely to be under-eating something else, usually something wholesome. Drink two litres of cola a day and you aren’t likely to be drinking milk for calcium and protein. Drink a bottle of wine each night and I doubt if you are eating much fruit. Eat lots of takeaways and your vegetable intake will suffer. Nutrition is just as much about “too little” as “too much”.

So whenever you see nutrition research being sold as the truth then always reflect on your own diet and ask:
  • Is it varied?
  • Is it nutrient-dense?
  • Is it minimally processed?
  • Is the emphasis on plant-based foods?

Answer yes to all four and there is a good chance you are eating well without having (boring) discussions about whether you should fuss about carbs or fat or the type of fat, or if there is a teaspoon of sugar in the house. We sadly forget that health is about the quality and nutrient density of food, the sentiment of which was captured in a recent article by Rosemary Stanton.

Smelling farts is good for you

Immediately you feel obligated to read this, don’t you? It was a common interpretation of a published research study by the media last year, especially in the UK. It’s a headline that will get plenty of attention, and the story exists only because people easily misinterpret science, leap to conclusions or get just too lazy to ask the study authors for an explanation.

If you have already clicked on the link and read the abstract, you will immediately see that it has nothing, absolutely nothing at all, to do with farting and your health.
Hydrogen Sulfide
It is a study about hydrogen sulfide (H2S), that smelly gas that is produced by your intestinal bacteria after they have chomped through the fibre in your meals. So any study about H2S must also relate to breaking wind, right?

Actually, the H2S story has its own fascination. From a physiological perspective H2S is called a gasotransmitter and has a really interesting role. Just so you know, nitric oxide (NO) and carbon monoxide (CO) are also gasotransmitters that you may have heard about.

All three gasotransmitters are vasodilators, which just means that they help your arteries to widen with ease, which in turn means that blood flows through easier. So, if the heart requires less pressure to pump blood through your arteries, then your blood pressure is lower. It doesn’t stop there. H2S also reduces the level of inflammation linked to heart disease, and is critical for the health of your mitochondria, famous for delivering energy for muscle contraction. And, because they are smart molecules, H2S, NO and CO all “talk” to each other to make sure they are all cruising through your body at ideal levels.

Depending upon levels, H2S is either toxic or healthy
While we knew that atmospheric H2S was toxic to the body for many years (and I don’t mean from passive farting, we are talking industrial waste levels here) it has only been since 1996 that we began to appreciate its role when very small amounts are manufactured within the body. Problems with the natural production of H2S have been linked to hypertension and diabetes, and conditions of chronic inflammation such as rheumatoid arthritis. When your body produces normal levels of H2S, you get up with a smile on your face and a zip in your step.

What does it all mean?
We make the same mistake all the time, assuming that a compound has a similar effect inside and outside the body. The classic example was assuming that cholesterol in food became cholesterol in blood, so everyone stopped eating eggs, yet body weight, genetics and maybe too much saturated fat are the real culprits. Just because H2S is very useful when manufactured by body cells, doesn’t mean that snorting your own gas emissions will have the same positive effect. The same goes for CO. Inhale car emissions in a concentrated space and you will eventually collapse and die. Yet the tiny bit of CO produced by your body is good for you.

As you know:
1. Nothing is bad; it is the amount that determines whether it is bad.
2. Journalists don’t specialise in science or asking smart questions.
3. By the time you have reached your 17th birthday you will have ignited some H2S. Ok, maybe not all the ladies. Just most.

Oh, why spell it sulfide and not sulphide? Because the Royal Society of Chemistry and the International Union of Pure and Applied Chemistry both spell it sulfide and you just don’t mess with purity and royalty.