Tag Archives: nutrition

Let the science speak for itself

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As epidemiologists go, Dr Dominik Alexander, is a surprise. He’s young, 39, doesn’t wear glasses or a white coat and is a previous professional kickboxer. However, the leading US epidemiologist also knows his stuff about cancer and nutrition research and he’s been over here in New Zealand sharing his expertise.

With extensive experience in health research methodology and interpretation of epidemiological studies, particularly nutritional epidemiology, Alexander is based in Boulder, Colorado, where he works for engineering and science consultancy firm Exponent Inc in its Health Sciences Centre for epidemiology, biostatistics and computational biology.

He delivers the sobering estimation that one in three people will be diagnosed with cancer in their lifetime. The strongest risk factor for cancer, generally, is age.

“With increasing numbers of older people, we are seeing higher rates of cancer and also diabetes and heart disease. This is also the case in developing countries, where the elimination of certain infectious diseases – which would have killed off more of the population early on – and lower infant mortality rates, means a higher rate of cancer and other age-related diseases in the population.”

Relating to nutrition, the types of cancer of concern are those associated with digestion, absorption and elimination such as the most common type, colorectal, through stomach/gastric to the less common oesophageal, pancreatic, liver and other cancers.

As an epidemiologist studying the patterns, causes, and effects of health and disease in defined populations, he’s involved in examining exposure and outcome.

“Food is a necessary exposure. All people have to eat,” he says, adding that the result of over-exposure leads to higher Body Mass Index (BMI) rates – overweight to obese – where there is an established increased risk for cancers such as colorectal, the most common cancer affecting the alimentary tract.

In his view, cancer prevention is all about control. The key is a health lifestyle. “It all starts with physical exercise and maintaining a healthy body weight.  In addition you need a well-balanced diet,” he says.

Opinions + assumptions + perception = confusion

Trouble is, as everyone eats, every single person has an opinion on it and the perceptions of the general public, the medical fraternity and the media vary. That’s why the ‘study of the moment’ is leapt on, over-hyped, over-analysed and consequently gets a lot of airtime leading to consumer confusion.

But, you can’t view a single study in isolation, he notes. “Every study needs to be viewed in the context of the available body of scientific views, otherwise it can be misinterpreted.”

Good science is at the heart of good communication, he believes. Dr Alexander’s advice for those communicating with the public is: “Don’t say anything that can’t be backed up by science. Let the science speak for itself and don’t make an interpretation outside the bounds of the scientific results. Given the complexity with this type of product, there needs to be a cautious approach.”

What media get hung up on sometimes is the people funding the research and conflicts of interest. That can negate the worth of the science itself, he believes. “It’s very important to get to the heart of the issue with science and then focus on the science and the scientific basis for comments.”

In his opinion, what makes good evidence is transparency, objectivity, justification for doing the research, rationale and a clear and open basis for research.

“A lot of problems come in when the research is not open and transparent. Say what you’re going to do, do it and show what you learned,” he advocates.

Looking to the future

Looking to the future, we have a long way to go on the preventative side, he says, and continuous updates of cohort studies, don’t always shed light.

“We also lack long-term evidence of differences between organic versus conventional products, for example.

“This all takes us back to the holistic approach and concentrating on the healthy body weights and lifestyle elements.”

Dr Alexander’s articulate delivery comes with a sense of humour and the surprising revelation that he was once a professional kickboxer in the 1990s, before he moved straight to science at the University of Alabama in Birmingham (UAB).

“You could call me the toughest epidemiologist in the world,” he laughs.

At UAB, he was awarded a National Cancer Institute Fellowship for Cancer Prevention and Control and worked closely with the Department of Pathology where he designed and implemented epidemiological studies pertaining to colorectal survival. He is also the 2010 recipient of the UAB School of Public Health Alumnus for scientific excellence.

Dr Dominik Alexander PhD MSHP was invited to Australia and New Zealand in September in a visit jointly organised by Meat & Livestock Australia and Beef + Lamb NZ Inc.

This article appeared in Pen & Palate (October 2012), the NZ Guild of Food Writers’ ezine.

Organic foods not more nutritious, says study

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The argument that organic food, including meat, is more nutritious than conventionally grown food has been cast doubt on by new research, based on an analysis of several hundred studies.

The study by Dr Crystal Smith Spangler and others, published in Annals of Internal Medicine (4 Sept), is the most comprehensive meta-analysis to date of existing studies comparing organic and conventional foods. Researchers analysed 237 separate studies which compared the organic foods to conventionally grown foods. They did not find strong evidence that organic foods are more nutritious or carry fewer health risks than conventional alternatives, though consumption of organic foods can reduce the risk of pesticide exposure.

As for what the findings mean for consumers, the researchers said their aim is to educate people, not to discourage them from making organic purchases. “If you look beyond health effects, there are plenty of other reasons to buy organic instead of conventional,” noted lead researcher Dena Bravata, from Standford University. She listed taste preferences and concerns about the effects of conventional farming practices on the environment and animal welfare as some of the reasons people choose organic products.

Professor Alan Dangour of the London School of Hygiene and Tropical Medicine, says like a review he and others conducted in 2009, this latest study “again demonstrates there are no important differences in nutrient content between organic and conventionally produced foods.” It also finds no evidence that organic foods are healthier than conventionally produced foods, he adds.

Organic driven by risk aversion

The majority of people who eat organic food are driven by risk aversion not nutritional superiority, believes Liza Oates, a PhD researcher into the health effects of organic diets and course coordinator of Food as Medicine, Wellness and Complementary and Alternative Medicine for the Master of Wellness Programme at RMIT University in Melbourne.

“Our research shows organic consumers are more interested in what’s not in their food – such as pesticides and antibiotics – than what is. Most also say that the environmental and social benefits of organic food play a key role in their decision to go organic.”

She points to US research that has shown that eating organic food has a dramatic effect on pesticide residues in children. “Substituting non-organic fruits and vegetables with organics for five days resulted in an almost complete reduction in organophosphate pesticide residues. It is this kind of benefit that many organic consumers are looking for when choosing to buy organic food,” says Oates.

 

Tesco to run hybrid nutritional labelling scheme

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UK retail chain Tesco, a major customer for New Zealand’s meat exporters, has had a change of heart over traffic-light nutritional labelling,  says online food trade magazine Just-Food.

This is a major change in strategy for Tesco which up to now has supported the Guideline Daily Amounts (GDA) approach, the magazine says. Responding to consumer research, Tesco made the announcement last week that it will now be using a hybrid labelling system, including both GDA and traffic light systems.

Philip Clarke, Tesco’s chief executive said Tesco has led the way by giving shoppers clear information about the food they eat and was the first retailer to put nutritional information on the front of its packs in 2005 when it rolled out its GDA labels.

“We always listen to our customers and they have told us by combining our popular GDA labels with traffic light colour coding we can make it even easier for them to make informed and healthy choices about the food they buy,” he said.

The news has been welcomed by British health minister Andrew Lansley, NGOs and public health groups.

The consumer research was conducted by Penn Schoen and Berland and involved 1,002 UK adults aged over 18 in a quantitative online survey.

 

Strengthening the nutrition platform

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Fiona Carruthers.

The meat industry, from food technologists to promoters, now has a credible technical resource for nutritional data on beef and lamb, thanks to a bank of recently completed assessments by Beef + Lamb NZ (B+LNZ) Inc, writes nutrition manager Fiona Carruthers.

Being able to provide nutritional information is becoming increasingly important. In the United States, for example, there is now a requirement that nutritional information must be shown on package labels for certain whole cuts of meat, such as steak, or displayed on charts at the store. Previously, this information was required only for processed foods or for meat products with added ingredients such as marinades or stuffing.

B+LNZ has recently undertaken a project to assess the nutritional attributes of over 50 cuts of beef and lamb. It is the largest analysis ever done on New Zealand’s red meat. Updating and expanding the nutrition composition database strengthens the platform on which all activities and communications are based. Sound science is an integral part of B+LNZ’s nutrition portfolio and this new analysis provides a credible technical resource accessible to everyone inside and outside the industry.

In this issue, details of the sampling and methodology used in the project are explained, as well as some top line results.

Sampling

Several criteria relating to sampling and methodology had to be fulfilled in order for the new data to be eligible for inclusion in databases globally.

Samples of beef and sheep meat for analysis were derived from meat processors across the country over a six month period. The need to obtain a representative number of samples from each region was deemed unnecessary as regional variation was thought to be minimal given New Zealand’s small geographical area. The same was true for the potential influence of breed or feed on composition; it was requested all samples came from New Zealand cattle and sheep raised and finished on pasture. All of the sheep meat analysed was ‘lamb’, that is under 12 months of age without any permanent incisor teeth ‘in wear’. An ‘average’ lamb carcase was determined by selecting from carcase grades in proportion to the national slaughter statistics. Beef samples came from P2 steer carcases – those classified as having light to medium fat cover with good muscle development – weighing between 270-320kg.

Lean and fat samples were analysed separately, giving the ability to provide compositional data for cuts with varying degrees of fat trim, or fully lean, as appropriate. The need for this flexibility is underlined by evidence showing many consumers trim fat after purchasing meat, either before or after cooking.

Methodology

For each of the 23 beef and 25 lamb cuts analysed, an average of 10 samples was collected to give a total combined sample of 3kg lean tissue for both cooked and uncooked product. Sample tissue was prepared by separating bone, fat and lean muscle by boning knife. Analysis was carried out on both raw and cooked samples, using appropriate cooking methods advised by B+LNZ’s food specialist. The diagram below  summarises the procedure followed up to the stage of freeze-drying.

Nutrition methodology flow-chart.

Widely-accepted laboratory procedures were used, in line with the requirements of international nutrient databases. A total of 25 nutrients, including proximate analysis, and 40 fatty acids were analysed in the lean and fat samples. Additional data in this new data set includes figures for long chain polyunsaturated fatty acids and vitamin D. Full amino-acid profiles were determined for four uncooked, lean cuts of both beef and lamb.

Results

Fat

The new data shows New Zealand beef and lamb continue to be low fat protein options for consumers, particularly when eaten trimmed of visible fat. Many cuts remain eligible for the Heart Foundation ‘Tick’.

  • Average total fat content across all lean cuts (uncooked) = 4.66g/100g for beef, 4.65g/100g for lamb
  • Average saturated fat content across all lean cuts (uncooked) = 2.17g/100g for beef, 2.45g/100g for lamb
  • Average cholesterol content across all lean cuts (uncooked) = 43.5mg/100g for beef, 63.5mg/100g for lamb

Omega 3s

Oily fish and other seafood are undoubtedly the richest sources of omega 3s. Lean red meat provides smaller amounts but contribution to the diet may be significant when relative amounts eaten are considered.

  • Average long chain omega 3s across all lean cuts (uncooked) = 41mg/100g for beef, 48mg/100g for lamb.

Vitamin D

Vitamin D is gaining an increasing amount of scientific ‘air-time’, both due to its importance in the diet and increasing levels of insufficiency seen in the New Zealand population and other developed countries. Meat has been viewed historically as a poor source of vitamin D, but 25-OH vitamin D3 is now being recognised as a more ‘potent’ form, with a potency factor of 1.5 – 5 suggested by researchers working in this area. Initial analysis of the vitamin D data shows 100g of beef or lamb can provide about 10% of the daily vitamin D requirement (NZ/Aus = 5μg).

Nutrient claims

Data suggests eligibility for a range of nutrient claims, for example ,g iron, zinc, protein and vitamin B12, according to the trans Tasman Food Standards Code, both as a ‘source’ (≥10% RDI) and ‘good source’ (≥25% RDI), as well as being low in sodium.

This new data confirms lean New Zealand beef and lamb can be promoted on its nutritional attributes. As a nutrient-dense food, a small serving of lean red meat gives large amounts of important nutrients for good health.

Further information is available from Fiona Carruthers, nutrition manager, B+LNZ. Email: [email protected].

Published in Food NZ (June/July 2012).

 

Red meat mortality claims rebuffed

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Courtesy: B+LNZ Ltd

A recent American study of 121,432 US health professionals has come to the conclusion that consumption of red and processed meats is associated with an increased risk of early deaths from cancer and heart-disease. However, nothing could be further from the truth say nutritional experts.

The Harvard University paper ‘Red Meat Consumption and Mortality’ authored by An Pan and Qi Sun, plus associates, appeared in Archives of Internal Medicine. It dealt with two long-term studies that ran between 1980 and 2008 of two cohorts of professionals and documented 23,926 deaths. The researchers quizzed participants on their eating and lifestyle factors.

The boldly-stated conclusion of the authors was that: “Red meat consumption is associated with an increased risk of total, cardio-vascular disease and cancer mortality. Substitution of other healthy protein sources for red meat is associated with a lower mortality risk.”

British qualified nutritionist and obesity researcher Zoe Harcombe, who has analysed the data, suggests there are numerous key problems with the study and says that “the study can at best suggest an observed relationship, or association. To make accusations about causation and risk is ignorant and erroneous.”

She also notes that the numbers are very small. “The overall risk of dying was not even one person in a hundred over a 28 year study. “If the death-rate is very small, a possible slightly higher death rate in certain circumstances is still very small. It does not warrant a scare-tactic ’13 percent greater risk of dying [from unprocessed red meat]’ headline – this is science at it’s worst,” she asserts.

Fiona Carruthers, nutrition manager for Beef + Lamb NZ agrees, pointing out that the methods used to try and predict risk of death from cancer and heart disease in this study are known to be inaccurate and unreliable. “The researchers themselves acknowledge the limitations of how they measured the amount of specific foods eaten, including red meat.”

Other similar studies have shown no risk at all, she says. “There are a number of risk factors for cancer and heart disease; obesity remains the most prevalent. Singling out one food in a condition influenced by such a wide range of factors is misleading.”

The scientific and medical communities agree eating lean red meat as part of a healthy, balanced diet is beneficial to health. It is an excellent source of protein, readily available iron, zinc, selenium, vitamin D and a range of B vitamins, as well as being a low-fat food.

“The results of a single study never change dietary advice or recommendations and this is no exception,” Carruthers says. “New Zealand beef and lamb contribute significant amounts of several nutrients to the diets of New Zealanders. Consumers should therefore be advised to continue to enjoy red meat three to four times a week as part of an overall healthy lifestyle.”

Published in from Food NZ magazine (April/May 2012).

 

New nutritional analysis confirms NZ meat packed with nutrients

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The most comprehensive nutritional analysis of New Zealand beef and lamb ever carried out confirms it is densely-packed with nutrients essential for everyday life.

The study, carried out by scientists in the Institute of Food, Nutrition and Human Health at Massey University, analysed 65 nutrients in almost 50 cuts of New Zealand beef and lamb, both raw and cooked.

High quality protein, easily-used iron and zinc and a variety of B vitamins remain the essential parts of red meat’s nutritional make up, but the study revealed some new additions.

“Long chain omega 3 fatty acid levels are higher in meat from animals raised on pasture compared to grain.  These new figures will be of particular interest to our customers overseas, as well as offering Kiwis additional health benefits,” says Professor Roger Purchas from Massey University.  “Our analysis also shows New Zealand beef and lamb contributes in a small way to dietary intakes of vitamin D”.  Worryingly low levels of vitamin D are being seen in Kiwi youngsters, so dietary sources are becoming increasingly important.

The new analysis also confirmed lean red meat as a low fat food, with an average fat content well below 10 percent.  This underlines results of the recent Ministry of Health 2008-9 New Zealand Adult Nutrition Survey, showing red meat’s contribution to dietary fat and saturated fat intakes falling to 6.8 percent and 7.3 percent respectively, dispelling the myth it is a main source of both fat types.

“As an industry, we strive to ensure all our nutrition messages are based on robust science, having undergone rigorous scientific scrutiny,” says Scott Champion, chief executive of Beef + Lamb NZ, which funded the research. “This study provides a solid platform from which to inform and educate all of New Zealand’s customers around the world about the goodness of New Zealand beef and lamb.”

Reproduced from Food NZ magazine (April/May 2012).