‘Pie hole’, colloquial for one’s mouth, is believed to have evolved in the USA in the 1980s from the British expression ‘cake hole’ (coined in the mid 20th century). Pie hole refers to a mouth, as in: Shut your pie hole or, in this case: Put less in your pie hole.

Wednesday, August 28, 2013

Bacteria: Public Enemy #1 Or Protective Posse?

The human gut is a fascinating and complex beast. Different sections are responsible for different elements of digestion and absorption of food. Perhaps one of the most enchanting aspects of digestion is the relationship we humans have with bacteria. Wait! Before you reach for your multipurpose cleaner that kills 99.9999% of germs, hear me out. They won't kill you, in fact, being without them might kill you. What am I on about? The human gut microbiome (duh).

The Human Microbiome Project, started in 2007, is a project that seeks to categorise microbial (bacterial) communities found at body sites including the nose, mouth, skin, genital tract and, of course, the gut.

The microbiome is a blueprint of the genetic configuration of all microbes inhabiting the body. Microbes in the gut are called 'gut flora'. Humans and gut flora boast a mutually beneficial (or symbiotic) relationship. Simply explained: They get food, nutrients and a "pimpin' pad", and we use them for health.

What precisely does this mean 'for health'? It sounds kind of wishy washy, like someone telling you taking multivitamins or antioxidants will improve your 'overall health'. Yep, we'll get right to that. Gut flora are important to our health because:
  • They promote a strong immune system by preventing the colonisation of pathogenic bacteria
    • Think of them as your neighbourhood watch, they keep out the bacteria that wreak havoc
  • They synthesise vitamins
  • They ferment non-digestible carbohydrates like resistant starch, cellulose, and pectins (in other words: Fiber)
    • Fermentation produces short chain fatty acids which promote cell turnover in both colon and liver cells, which decreases cancer risk
Gut flora profiles differ between individuals and, unlike the human genome (one's DNA), they can be altered. For example, obese people have different gut flora, and usually a lower diversity, compared to healthy weight individuals. Research shows certain gut bacteria are correlated with obesity and metabolic syndrome traits including elevated blood glucose, cholesterol and triglyceride levels. The phrase 'you are what you eat' is perhaps more accurately 'your gut bacteria are what you eat'.

Another piece of the gut puzzle to pique your interest, is the role stress plays on your colon and its inhabitants. Stress can provoke unsavoury changes to your usual colon function... Everyone's favourite words: Diarrhea and constipation. Often these occur due to changed eating habits. Whether it's skipping meals, eating more fast food, or eating less of your high fiber foods (whole grains, fruit and veg), diet changes often upset the bacteria in your intestines, resulting in said unpleasant side effects.

Key messages and tips to write home about:
  • Your gut/colon/large intestine, whatever you want to call it, plays a fundamental role in health beyond food digestion
  • Foods in your diet, your weight status and stress levels impact your gut bacteria
  • In times of stress, the best way to prevent disagreeable bowel upsets like diarrhea and constipation (oh dear, said it again), is to continue eating your usual (healthy) diet

Wednesday, August 21, 2013

Frankenburger: I'm Lovin' It

News of the first lab-grown beef burger sure was a juicy topic world wide. Amongst the media frenzy were quite a number of interesting opinions: From "this 'meat' could be accepted by vegetarians", to opinions stating lab-grown meat is not more environmentally friendly than conventional meat production, to comments about the nutritional quality of the product. Several people have solicited my perspective, so I proceeded to do what any normal person would... delve into the research and write an article about it.

The burger that was cooked and consumed on Monday August 5th at a television studio in London, was the culmination of five year's work by Dr. Mark Post at Maastricht University in the Netherlands. Conservative estimates re the cost of this research is around $5 million, and the test burger cost a nifty $325,000. Google founder Sergey Brin, donated $1 million to help fund Post's research.

Now you're all caught up on the back-story, onto some different numbers: Environmental impacts. When I first read about lab-grown meat, I had my doubts about it being that much more environmentally friendly. In the end, you have to run a lab, support and monitor tissue growth, run tests, exercise the muscles, etc. These require electricity, water and resources that produce their share of greenhouse gasses.

A recent study showed lab-grown meat has, overall, substantially lower environmental impacts compared to conventionally produced meat, see Figure 1 (not to mention the reduction in feed required, or the ethical aspects associated with conventional meat production). Highlights:
  • Energy use in lab-grown meat was 7-45% lower than conventionally produced meat
    • Poultry was the exception
  • Greenhouse gas emissions were 78-96% lower in lab-grown meat
    • Lab-grown tissues don't fart
  • Land use was 99% lower 
    • A no-brainer really, meat in a lab doesn't need to walk around and graze all day
  • Water usage was 82-96% lower in lab-grown meat
    • A sobering thought: Conventional beef requires ~2,500 gallons (almost 10,000 liters) to produce just 1 pound (450g) of beef
Figure 1: Adapted from: Environmental Impacts of Cultured Meat Production
Environmental Science and Technology: 2011, 45 (14) pp 6117-6123
An interesting question, though, is that of nutritional quality. The lab-grown burger had no fat in it, which must impact taste and texture to a degree. But also, it could change the bioavailability (degree of absorption and use by the body) of fat soluble vitamins - which need fat for optimal absorption.

Another nutritional question is that of the bioavailability of vitamins and minerals in the meat. Because lab-grown meat doesn't have a circulatory system and isn't being 'fed' by the animal, vitamins and minerals may need to be artificially introduced for the cells to function optimally. We know in humans that vitamin and mineral supplements are less bioavailable than those found in actual food. Will the vitamins and minerals in lab-grown meat have the same bioavailabilty as conventional meat?

There is no research in this area yet, so what comes next are my best 'edumacated' opinions:
  • If supplements are artificially introduced to lab-grown cells, it stands to reason that doses are carefully monitored to provide only the amount required for cells to function
    • Not at the excessively high doses humans take when using supplements
  • The cells will assimilate these nutrients the same way a cell in a living animal would - so they can continue to function, produce energy and survive
    • If the vitamins and minerals are assimilated into the tissue, they should behave the same as nutrients in conventional meat when ingested by humans
But again, these are just opinions. Time and research will inform us. In the meantime, the omnivores amongst us will continue to content themselves with conventionally produced meat, much to the disgust of their vegetarian counterparts. No paradigm shift... Yet.

Wednesday, August 14, 2013

Should You Ante Up in the Oxidant Game?

They're in the news, they're hailed on many food labels, and they're also stealthily hiding in uncelebrated, under-marketed and unpackaged fruits and vegetables. What am I on about? Antioxidants. Join us on this juicy journey as we unmask these mysterious molecules that many claim will keep you young, healthy and disease-free.

What are oxidants, and why is everyone so anti them?

Oxidative stress is caused by 'free radicals'. Free radicals contain an unpaired electron which, for those of us who remember some rudimentary chemistry, means they are unstable and want to either accept or donate an electron. They can cause cellular damage (oxidative stress) by 'bumping' into other molecules, proteins and DNA. Think of them as hyperactive kids running around at a birthday party - they unpredictably knock into things and usually damage something.

Production of free radicals is a perfectly normal bodily process. Metabolism and exercise produce them internally, as well as external sources like pollutants and cigarette smoke.

At moderate concentrations, free radicals are actually really important in regulatory processes like cell signalling. It's at sustained, high concentrations that they are problematic and play a role in disease development. This is where antioxidants come in: Antioxidants are compounds that safely react with free radicals before they cause cellular damage. Think of them as your spam filter.

'Antioxidant' is a broad term. Based on my observations, and eavesdropping on the occasional Costco conversation, most antioxidant spruikers couldn't actually define the term 'antioxidant' to save their life. Most don't realise that both vitamins and minerals are antioxidants, as well as 'non-nutrient' compounds like phytochemicals (found in plants). When most people drop the keyword 'antioxidant', it's like a child dropping the f-bomb... They have no idea what it really means.

Oxidative stress, or excessive concentrations of free radicals, is associated with the development of  several diseases including atherosclerosis (hardening of the arteries), heart disease, Alzheimer's disease, joint inflammation, cancer and type II diabetes. So why not turn to antioxidants?

Several meta analyses (combination and analysis of independent studies) show large supplemental antioxidant doses do not prevent the incidence or progression of these diseases. In some cases, one example is beta carotene in smokers, it actually increases the risk of smoking related cancers and cancer death. Another analysis of 56 studies showed supplementation with antioxidants significantly increased risk of death. One meta analysis reported a potential benefit of low dose vitamin B6 and vitamin E... But, and there's always a but, those studies had the vitamins provided by pharmaceutical companies (which calls into question the legitimacy and accuracy of testing protocols/results, given this conflict of interest). Additionally, when only looking at high quality studies, the benefits of B6 and vitamin E were not supported.

So now I'll put my dietitian hat back on... Research shows people who eat large amounts of fruits and vegetables (Australian guidelines recommend 2 serves of fruit and 5 of vegetables, the US guidelines recommend 2 serves of fruit and 2-3 serves of vegetables) have lower rates of oxidative stress and associated diseases. It's unclear whether antioxidants, or something else is responsible (ie: the health benefits of eating a high fiber diet). But results are results: Plain old foods like cheap, humble fruits and vegetables prevent diseases better than artificial, man-made pills... Shocker.

The paradox here is that antioxidants are important for health, but too much of a good thing appears disadvantageous. If we go back to the spam filter analogy, we want a spam filter to keep out emails that contain viruses, obnoxious sale items, porn, etc, whilst still letting through emails from friends, family, work, etc. Having a mega spam filter tends to keep out the important emails we still want.

Take home points and tips:
  • Antioxidants come from many different kinds of foods that also contain fiber and other health supporting characteristics
    • Fruits, vegetables, whole grains, nuts, herbs, dairy, lean meat and seafood
  • Eating a varied and balanced diet provides us with a the necessary array of antioxidants that keep our bodies healthy with the right balance of free radicals
My apologies again to the pill popping, just-want-a-quick-fix crowd... There is just no supplement for real food.

Wednesday, August 7, 2013

Cutting Carbs: A Cockamamie Idea

It's been in the news and under the spotlight for many years now:  Low carbohydrate diets. This topic doesn't require much of an introduction. So let's jump right in, what does the science say about low carbohydrate diets?

First off, a little history. Robert Atkins began promoting the low carbohydrate approach to weight loss in the 1970s, based on a research paper written in the late 1950s (that's a mighty old study). The diet was revamped in 2002 with the release of his second book on the topic.

Next up, what is a carbohydrate? Carbohydrates, or 'carbs' are one of the large nutrient classes. When digested, carbs break down into sugars that are used by cells, tissues, muscles and organs. Interestingly, the brain can utilise ketones (byproduct of fat breakdown) for energy, but preferentially and primarily uses glucose (a sugar) to function. Perhaps the 'carbs are evil' mantra is a result of carb cutter's suffering from declining brain activity. See figs 1 & 2 for types of carbs and number of daily serves recommended.
Figure 1: What a serve of carbohydrate looks like and number of serves recommended for adults (adapted from the Australian Guide to Healthy Eating 2013)
Figure 2: Examples of a serve of carbohydrates (adapted from the Australian Guide to Healthy Eating 2013)
A recent meta analysis (combination and analysis of independent studies) found short term weight loss benefits for low carb dieters... But (and there's always a but) no long term cardiac (heart) benefits were found. In fact, those on long term low carb diets had an increased risk of death. Hypothesised reasons for this:
  • Low carb diets are generally higher in protein
  •  Low carb diets are generally low in fiber
    • Many fruits are restricted, as are whole grains (oats, wheat, rice, pasta, legumes)
    • These are both extremely good sources of fiber - evidence shows high fiber diets are protective against many cancers, heart disease and high cholesterol
In the short term, favourable effects of a low carb diet are seen with regard to weight loss and improved blood sugar control.

Let's think about that: It stands to reason, because poor blood sugar control in someone who eats excessive carbohydrates causes insulin resistance - where the body must produce more than normal amounts of the regulatory hormone that controls blood sugar - insulin. If you decrease the carbs being eaten, of course blood sugar levels will improve... Duh. That's like saying, I will continue to be drunk if I continue drinking alcohol vs sobering up if I drink less.

The take home messages and tips:
  • Research does not support long term low carb diets
    • A better method is changing your eating habits long term, rather than a 'diet' (something you start and stop)
  • Putting whole grain sources of carbohydrates in your pie hole is beneficial for your health
    • They provide fiber, slow releasing energy and reduce the risk of cancers, type II diabetes and heart disease
    • Eating carbohydrate foods (Figs 1 & 2) ensures not overeating protein to compensate for removing/restricting a whole food group

    For more information about daily serves of grains and how grains contribute fiber to your diet, see: