Eggs – Back on the menu?

Egg_coloursThere has been a flurry of news reports following on from the publication of the US government’s ‘Scientific Report of the 2015 Dietary Guidelines Advisory Committee’ which included the tacit admission that the guidelines which have been in place for decades got it fundamentally wrong when it comes to cholesterol. If you take a look at Part D, Chapter 1 you can see this little gem:

Cholesterol. Previously, the Dietary Guidelines for Americans recommended that cholesterol intake be limited to no more than 300 mg/day. The 2015 DGAC will not bring forward this recommendation because available evidence shows no appreciable relationship between consumption of dietary cholesterol and serum cholesterol, consistent with the conclusions of the AHA/ACC report. Cholesterol is not a nutrient of concern for overconsumption.

Effectively tens of millions of people are taking cholesterol reducing drugs – statins – on the basis of guidance which is unsupported by the evidence. For years those doctors and scientists who dared to question the ‘self-evident’ truth that cholesterol was a killer were labelled as cranks or deniers. Well, it turns out that the sceptics were right all along. That statins work to reduce cholesterol levels is clear and undisputed – that this is related to reductions in cardiovascular events and overall mortality remains a matter of considerable dispute – and it’s not something that I want to get into here.

However, what I do want to point out is that as part of the anti-cholesterol dogma that was inflicted on us by our governments for a considerable period was the advice to cut down on foods which were high in in cholesterol – and that included eggs. One effect of this has been a reduction in our consumption of eggs – as shown by these figures from the US Department of Agriculture.

egg consumption

Now that cholesterol is on the way to being rehabilitated, we can take a look at what the science says about egg consumption. Is it good or bad? Safe to put eggs back on the menu or not?
A review published in the American Journal of Clinical Nutrition in 2013 looked at the data from 16 different studies, covering data from 22 independent cohorts (groups of people) and with follow-up periods of between 6 and 20 years. Pooling all of this data together in a meta-analysis that looked at a range of measures related to cardiovascular disease. The conclusion?

…egg consumption is not associated with the risk of CVD and cardiac mortality in the general population

There was a proviso though, those in the group with the highest consumption of eggs had an increased risk of developing type II diabetes. And in patients with type II diabetes, higher egg consumption was associated with a greater risk of cardiovascular disease. At this point it’s only fair to point out that taking statins to reduce your risk of cardiovascular disease also increases your risk of developing type II diabetes, but that’s a different story…
So, I think it’s fair to say that eggs can safely go back on the menu.

But if there’s a take home message here, it’s that we really do need to be more sceptical when it comes to ‘scientifically’ driven policy messages…

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Saturated fats – friend or foe?

pack-butterA reduction in dietary fat consumption, especially saturated fat, has been at the cornerstone of official dietary advice for as long as most of us can remember. Saturated fats are primarily animal fats, including dairy fat – think cheese, butter, lard, eggs – and from a few vegetable sources such as coconut oil. For example, the NHS Live Well website lists reduction in saturated fats as a key objective, suggesting that: ‘Eating a diet that is high in saturated fat can raise the level of cholesterol in the blood. Having high cholesterol increases the risk of heart disease.’ As a guideline amount the recommendation is set at no more than 30g of saturated fat a day for men, and for women it’s no more than 20g a day. On the other side of the pond the official advice in the Dietary Guidelines for Americans suggests reducing saturated fats so that they supply less than 10% of daily calories. The rationale is similar – saturated fats are associated with obesity and risk factors for cardiovascular disease. This is effectively the consensus opinion from government health agencies across much of the world, not just the UK and US However, the question we have to ask is does the evidence support this advice?

The obvious point is to ask what evidence there is for the core idea that reducing dietary saturated fat intake makes a difference to health. The answer is that there’s not much. A good place to start is to look at the evidence from clinical trials where dietary fat intake has been modified to see what it does in terms of health and those cardiovascular risk factors. What we’re interested in is human data here, not animal models. More than that, we’re interested not in the molecular effects or the variation in differing serum lipid fractions, we’re interested in actual health outcomes. Luckily some of the hard work in looking at the data has been done for us by the good people at the Cochrane Collaboration (a global not-for-profit project involving thousands of scientists working to analyse data and perform systematic reviews of evidence in medicine).

The Cochrane Heart Group have carried out a meta-analysis of clinical trials that looked at both dietary fat reduction and modification to see what effect these had in cardiovascular disease. Where the meaning of fat reduction is clear, fat modification means swapping the relative share of types of fat (saturated, polyunsaturated and monounsaturated) in the diet. The review looked at the data from large interventional trials that tracked health outcomes over a reasonably span of time (> 6 months). In all the data covered 48 randomised clinical trials, and the headline result is plain – there is no clear effect of dietary fat changes on total mortality or cardiovascular mortality.

Continue reading

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Obesity – fats and figures

The work I started here looking at the facts and figures on food intake and obesity –  specifically the posts here and here – have turned into an article on the Register. While I don’t think the sub-editor has quite got what the article was saying (the title of ‘Lies, damn pies and obesity statistics: We’re NOT a nation of fatties’ was not mine…). It’s interesting to look at the reader comments – very few of them are actually about what the evidence is showing…)

 

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Food Intake – What About Class?

In the last post I wrote about the causes of obesity and the common assumption that changes in our food intake are the cause. In particular the idea that we’re all eating more in the way of sugars and that this is what is causing the ‘obesity crisis’. Unfortunately the data from the UK government refused to go along with those assumptions. Surprisingly perhaps what the data showed was that our calorie intake has declined since 2001, and that this decline is across the major food classes – fats, proteins and carbs have all gone down over that period. What’s more, as the figures I pulled up showed, the proportions of energy intake from those three food groups has remained pretty constant.

One of the comments raised in response to those figures is that there must be some socio-economic factors hidden in the data, which combined all groups into one statistical average. So, the next thing is to just take a peek at the more granular detail to see what’s lurking. To that end, here’s a look at the total calorie intake for the lowest, middle and highest deciles (10% bands): Continue reading

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Why are we getting fatter?

Like most people I’ve accepted as gospel the idea that there is an ‘obesity’ crisis, and that this is due to changes in what we eat. Over time, or so we’ve been led to believe, we’ve been eating more and more, and of this increased food intake we’ve been eating more of the ‘wrong stuff’. Now for a long time the ‘wrong’ stuff was supposed to be fats, especially saturated fats which have been public health enemy No. 1 for years. Fats, we’ve been told, are the cause of heart disease, metabolic syndrome, obesity and cancer. Recently though there’s been something of a backlash as the science behind these public health messages just doesn’t stack up.

So, if fats are no longer the culprit, what is? The new public health enemy is sugar. And now some of the same people who’ve been warning us off fats and on to carbohydrates and sugar and now turning around and proclaiming that it’s the carbs that are behind obesity, cancer and all else that ails us.

But being of a sceptical nature I like to look at the evidence. And in this case there are some really good data sets to look at. For the UK we have the government’s own figures here: https://www.gov.uk/government/statistical-data-sets/family-food-datasets

So, what does the data say? Are we guzzling more and more and eating ourselves fat and unhealthy? Continue reading

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Chocolate and acne

512px-Chocolate

For those people who thought that eating chocolate gave you spots, there’s some good news – you were right. While this is good news for those people who always like to be proved right, it’s bad news for those people who love chocolate and are prone to acne. Thanks to a small clinical trial in the United States the evidence is in. The trial in question is reported in the Journal of Clinical and Aesthetic Dermatology (and available to read for free here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4025515/). This was a placebo controlled trial, which meant that one group of patients received capsules of unsweetened 100% chocolate, another group received capsules containing gelatine and another group capsules containing a mixture. This was also a double-blinded trial, which meant that neither the doctors nor the subjects of the study (men between the ages of 18 and 35 with pre-existing acne) knew who was getting the choc and who was getting the placebo capsules.

The men were assessed at day 4 and day 7 of the study and the number of acne lesions counted. And the results showed that there those who had the choc were more likely to have spots than those that didn’t. That’s the bad news. But there are some things to keep in mind. Firstly, this is a tiny study with data from only 13 participants. That’s a really tiny number to be using for a study with different doses and treatment groups. What’s more, when the authors looked at the correlation between chocolate dose and number of spots the numbers were tiny – if there’s an effect then it’s not very strong.

So, what can we conclude from this? Only that there’s some evidence to support the idea that chocolate consumption might increase the number of spots for people already prone to acne. But the strength of the connection is not especially strong. Personally if this was a problem for me I would carry out my own experiment. Stop eating chocolate for a while, take a few selfies for a few days, then binge on some choc that you enjoy, follow up with a few more selfies and then compare. Do you see a difference? Repeat a few times and see if there’s a repeatable effect. From this you can conclude whether chocolate has an effect on you personally and maybe even make an assessment of how big the effect it is.

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Rheumatoid arthritis and probiotics

I wrote in my last post about the positive health effects of probiotics in a range of health conditions. Two recent papers have reported results from a small clinical trial in women with rheumatoid arthritis. In this randomised double-blinded clinical trial (in other words, this is the most rigorous form of clinical trial in which neither doctors nor patients know who is being treated with the drug and who is being treated with a placebo), the ‘drug’ group received a capsule of probiotics (containing 108 colony forming units of Lactobacillus casei 01), while the control group received a lacebo (a similar looking capsule with no pro-biotics in it).

The treatment lasted for eight weeks and was assessed by looking at various inflammatory markers from the blood (IL-1beta, IL-6, IL-10, IL-12 and TNF-alpha), as well as assessing how symptoms changed over time. The good news was that the women in the treatment group registered changes in these inflammatory markers and also decreased tendernes and swelling in the joints and did better in terms of symptoms than the control group. There were no side-effects to the treatment either.

The trial concludes that ‘Probiotic supplementation may be an appropriate adjunct therapy for RA patients and help alleviate symptoms and improve inflammatory cytokines.’

In other words, taking probiotics has a measurable effect that has been proven in a clinical trial and might well provide some benefit to people with rheumatoid arthritis.

Note that this study used pro-biotic tablets, which are easily available, but it’s possible that there some of the benefits could come from eating foods that are high in probiotics, such as yoghurts and pro-biotic drinks.

The papers reporting these results are not available for free download – unfortunately they are not published as open access. You can view one of the abstracts here: http://www.ncbi.nlm.nih.gov/pubmed/24673738

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Yummy Yoghurt

685px-Cacik-1

I recently looked at the relationship between yoghurt consumption and cancer incidence over at the anticancer.org.uk website, a relationship that suggests that probiotic yoghurt consumption was protective against cancer both for those who eat a ‘fast food’ diet and those women with a genetic predisposition to breast cancer. My article was triggered by the publication of a new piece of research that looked at cancer development in mice, and if you haven’t read the piece I’d certainly suggest it’s worth a few minutes of your time. My interest piqued, I’ve dug a little deeper into the health benefits of probiotic yoghurt, and for those of you who love the stuff, it’s pretty much all good news.

First up is a paper by the same group who did the cancer study. In a paper entitled ‘Microbial reprogramming inhibits Western diet-associated obesity’,  published in the open access journal PLOS One, the authors found that mice fed a ‘fast food’ diet tended to develop obesity as they aged. And, as part of that obesity, these mice displayed inflammatory changes to their immune systems, much as happens in people with  obesity or metabolic syndrome. This is one of the drivers for people to try out various ‘anti-inflammatory and anti-oxidant’ diets after all. In contrast to all this, the same type of mouse fed the same ‘fast food’ diet but with added probiotic yoghurt avoided the age-related obesity and the inflammatory changes in the immune system. So, just in case you didn’t get that the first time, these researchers discovered that the addition of probiotics to an existing ‘bad’ diet seemed to stop the side-effects of that poor diet. The same researchers dug deeper and found that it was the effect of the probiotics on specific species of immune cells that made all the difference.

If that isn’t good news on it’s own, looking into the literature we can find more evidence that yoghurt is good for you. You might not be convinced that what’s good for a mouse is likely to be good for a person. In general it’s right to be sceptical about mouse models and human health. So what about some evidence in people?

Type II diabetes is a condition that is age-related and is also driven by inflammation and oxidative stress, so if what the mice results suggests is true then we should see something here, right? And in we look at a human trial published in 2012, we do indeed see something interesting. In this trial they compared the effect of probiotic versus conventional yoghurt in patients with type II diabetes. Two groups of patients were compared, each consuming the same amount of yoghurt every day (300 g per day, if you’re asking) over a 6 week period. And at the end of that time the probiotic group showed significantly decreased blood glucose and HbA1c levels, and significantly increased anti-oxidant status. And just to show that even conventional yoghurt is good for you, both groups showed significantly reduced serum malondialdehyde concentration (a marker for oxidative stress) compared to the base-line before they started the trial.

This isn’t the only such result, there are plenty more. My personal favourite is a paper entitled: Probiotic bacteria induce a ‘glow of health’. In this one the authors find that feeding mice probiotics produces radiant skin and fur, even in elderly mice, and that it made them look younger and fitter. Yep – if you’re an elderly mice and you want to look young and attractive again then tuck into some of that probiotic yoghurt. Unfortunately there’s no news on whether this one is going to be followed up with a human trial.

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healthy peanut butter

There’s a popular view that foods that are good for you are necessarily boring or tasteless. Put another way if it tastes good then it must be unhealthy. Well a new piece of research suggests that at least one ‘naughty’ food is good for you – if you’re young and female at least. In a study involving over 9000 young women, researchers tracked the intake of vegetable fats and proteins to see if there was any influence on later benign breast disease or breast cancer. The result was clear enough – to quote from the abstract of the paper:

The greatest sources of vegetable fat and protein in these girls were peanut butter, peanuts, nuts, beans (beans, lentils, and soybeans), and corn. A daily serving of any one of these was associated with lower risk (OR = 0.32/(serv/day), 95 % CI 0.13–0.79; p = 0.01). Peanut butter (and nuts) at age 11 years was inversely associated with risk (p = 0.01). In analyses of intakes at age 14 years, vegetable protein was associated with lower BBD risk (OR = 0.64/(10 gm/day), 95 % CI 0.43–0.95; p = 0.03). A daily serving at 14 years of any one of the foods was associated with lower risk (OR = 0.34, 95 % CI 0.16–0.75; p = 0.01), as was peanut butter (and nuts) (p = 0.02). Girls with a family history of breast cancer had significantly lower risk if they consumed these foods or vegetable fat. In conclusion, consumption of vegetable protein, fat, peanut butter, or nuts by older girls may help reduce their risk of BBD as young women.

In other words, eating peanut butter reduced the incidence both of benign breast disease and, for girls with a family history of  breast cancer, it reduced the chance of getting breast cancer.

Not bad for peanut butter – a food that has had a bad press over the years because of concerns about the sugar, salt and oils in it. However, there’s mounting evidence that peanut butter is definitely a healthy food that just happens to taste great.

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Book Review – Foods To Fight Cancer

Cancer patients, and their friends and families, are often faced with contradictory information on what to do about diet. On the one hand there are large numbers of mainstream oncologists and dieticians who tell patients to eat what they like so long as they keep the calories up and are able to get through chemotherapy or radiotherapy. On the other hand there are plenty of people who insist that only a strict vegan or macrobiotic or Gerson or other anti-cancer diet will help. And of course there are lots of books out there that advocate all kinds of diets, all of them claiming to be based on some sort of science. Those looking for a middle ground based on solid science are left trying to work out for themselves what makes sense and what is obvious nonsense.

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Foods To Fight Cancer looks like lots of other books in the ‘superfoods’ genre. It’s glossy, well illustrated and published by Dorling Kindersly. It looks more coffee table than operating table. However, unlike many of the anti-cancer food books that are on the market this one is written by scientists working in the field of diet and cancer and who are not only up-to-date with the science but who are engaged in making it happen. It just so happens that Richard Beliveau and Denis Gingras are excellent communicators able to write for the non-scientist as well as their colleagues.

The central premise of the book is that dietary interventions can help tip the odds against developing cancer, and also to aid in fighting cancer once it has started. The plant kingdom contains thousands of phytochemicals – polyphenols, terpenes, sulphides etc – which have potent anti-cancer properties. These micro-nutrients act in multi-faceted ways to block many of the different biological pathways necessary for cancers to form, grow and then metastasize. Unlike some of the over-inflated claims made by some, there is no promise of a single all-powerful cancer cure here. Instead the emphasis is firmly on looking at what pathways are necessary for cancer to develop and then what can be done to block these using multiple compounds from different foods. Continue reading

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