Colon cancer, gut microbes and your diet

A typical Western diet, rich in meat and fats and low in complex carbohydrates, is a recipe for colon cancer, Professor Stephen O’Keefe from the University of Pittsburgh, USA, told the Society for General Microbiology meeting at Harrogate today (Tuesday 31 March). He described an expanding body of evidence to show that the composition of the diet directly influences the diversity of the microbes in the gut, providing the link between diet, colonic disease and colon cancer.

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People eating a healthy diet containing high levels of complex carbohydrate (e.g., whole grains like wholewheat bread, brown rice, quinoa, millet, vegetables, fruit) had significant populations of micro-organisms in their gut called Firmicutes. These bacteria use the undigested residues of starch and proteins in the colon to manufacture short-chain fatty acids and vitamins such as folate and biotin that maintain colonic health. One of these fatty acids, butyrate, not only provides most of the energy to maintain a healthy gut wall, but it also regulates cell growth and differentiation. Both experimental and human studies support its role in reducing colon cancer risk.

However, gut microbes may also make toxic products from food residues. Diets high in meat will produce sulphur – this decreases the activity of ‘good’ bacteria that use methane and increases the production of hydrogen sulphide and other possible carcinogens by sulphur-reducing bacteria.

“Colon cancer is the second leading cause of cancer-related deaths in adults in Westernized communities.” said Professor O’Keefe, “Our results suggest that a diet that maintains the health of the colon wall is also one that maintains general body health and reduces heart disease”.

“A diet rich in fibre and resistant starch encourages the growth of good bacteria and increases production of short chain fatty acids which lessen the risk of cancer, while a high meat and fat diet reduces the numbers of these good bacteria.” Professor O’Keefe went on. “Our investigations to date have focused on a small number of bacterial species and have therefore revealed but the tip of the iceberg, our colons harbour over 800 bacterial species and 7,000 different strains. The characterization of their properties and metabolism can be expected to provide the key to colonic health and disease”

To learn more about which foods help to maintain the health of your gut and how to cook delicious recipes using them, please come along to a Cooking for Health course, held throughout the year in Somerset, UK.

Obesity reduces life expectancy by 3 to 10 years

A new analysis of almost one million people from around the world has shown that obesity can trim years off life expectancy.

The Oxford University research found that moderate obesity, which is now common, reduces life expectancy by about 3 years, and that severe obesity, which is still uncommon, can shorten a person’s life by 10 years. This 10 year loss is equal to the effects of lifelong smoking. 

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The analysis brought together data from 57 long-term research studies mostly based in Europe or North America. People were followed for an average of 10 to 15 years, during which 100,000 died, making it the largest ever investigation of how obesity affects mortality. It was coordinated by the Clinical Trial Service Unit (CTSU) in Oxford and the results are published online (28 March) in The Lancet

The studies used body mass index (BMI) to assess obesity. BMI is calculated by dividing a person’s weight in kilograms (kg) by the square of their height in metres (m). If a person has a BMI of 30 to 35, then they are moderately obese; if they have a BMI of 40 to 50, they are severely obese. Though not perfect, BMI is useful for assessing the extent to which fatty tissue causes ill health. 

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Among the 900,000 men and women in the study, mortality was lowest in those who had a BMI of 23 to 24. This means that if a person were 1.70m (5 feet 7 inches) tall, for example, his or her optimum weight would be about 70kg (154 pounds or 11 stone). 

This study has shown that continuing to smoke is as dangerous as doubling your body weight, and three times as dangerous as moderate obesity.

Epidemiologist Dr Gary Whitlock of Oxford University, who led the analysis, said of the findings:

”Excess weight shortens human lifespan. In countries like Britain and America, weighing a third more than the optimum shortens lifespan by about 3 years. For most people, a third more than the optimum means carrying 20 to 30 kilograms [50 to 60 pounds, or 4 stone] of excess weight. If you are becoming overweight or obese, avoiding further weight gain could well add years to your life.”

Comparing the effects of obesity with those of smoking, the study’s main statistician, Oxford University Professor Sir Richard Peto, said:

“This study has shown that continuing to smoke is as dangerous as doubling your body weight, and three times as dangerous as moderate obesity. Changing your diet but keeping on smoking is not the way to increase lifespan. For smokers the key thing is that stopping smoking works.” 

In those who were moderately obese (BMI 30 to 35, which is now common), the lifespan was reduced by three years. Severe obesity (BMI 40 to 50, which is still uncommon) reduced life expectancy by about 10 years; this is similar to the effect of lifelong smoking. Although severe obesity is more common in North America than in Europe, in both places it is much less common than moderate obesity, which has only a third of the effect on lifespan that smoking does.  

There was also a higher death rate among those who had a BMI well below 23 to 24, mainly because of strong inverse associations with respiratory disease and lung cancer. This hazard was much greater for smokers than for non-smokers.

Obesity increases death rates for some types of cancer, but the main way it kills is by increasing risk of heart disease and stroke. Amongst middle-aged people in the UK, as many as one in four deaths from heart attack or stroke and one in 16 cancer deaths are due to being overweight or obese. In the US, where middle-aged people are typically a few kilograms heavier, the figures are even higher: one in three heart attack or stroke deaths and one in 12 cancer deaths in the US are due to being overweight or obese.

Have you spent years embarking on every weight-loss diet going? Have you tried cutting out entire food groups? Have you spent a fortune on miracle foods or diet powders? Have you eaten nothing except cabbage soup for weeks? Have you driven your friends mad with your fervour over food combining? Have you become obsessive about counting calories or points? Have you spent hours jumping on and off your bathroom scales? Do you feel hungry much of the time, exhausted and beset by cravings?

Our bodies evolved over millions of years to work perfectly with a diet of naturally available unprocessed foods. Our ancestors were not fat because they ate this optimum diet and exercised every day. Today, some societies in the world maintain this traditional type of diet and remain lean and at low risk of diabetes, heart disease, cancer and dementia.

You can learn how to lose weight effortlessly without feeling hungry, whilst gaining health and vitality, at a Cooking for Health class on “Managing Your Weight Naturally“. We explore why so many diets fail and explode many of the weight loss myths. We look at cravings – how they arise and how to overcome them – and we discuss which foods the body needs to create energy and burn fat in the most efficient way. We create a delicious meal with an array of different dishes designed to illustrate how it is possible to eat plenty without gaining weight.

Why mothers don’t breastfeed

Breastfeeding rates in the UK are much lower than in many European countries. Less than 1 per cent of mothers in the UK are exclusively breastfeeding at six months. 

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A focus group study in the UK suggested a number of reasons why women may not breastfeed or why they stop breastfeeding early. These were as follows: 

  • The attitude of other people – women felt that breastfeeding in public was unacceptable and embarrassing, while bottle-feeding was accepted by everybody and in all places. A lack of places to breastfeed out of sight restricted women’s ability to get out of the house. This may be a bigger issue for low-income women, who may not have the option of breastfeeding in the car. Some women reported breastfeeding in public toilets as the only option. Women wished that cafés and shops could provide places to breastfeed with some privacy.
  • Attitudes of family and friends – some women said that even family and friends found it ‘repulsive’ to be in the same room when they were breastfeeding. Some grandparents thought it excluded them from having the chance to feed the new baby. It was clear that the opinion of family and friends was a stronger influence than that of health practitioners. 
  • Lack of knowledge – women vaguely knew that breastfeeding was supposed to be beneficial, but they could not name any benefits, and were not convinced about them. In the study only one woman had learnt at school about benefits of breastfeeding; most did not hear about it until they were pregnant. Feeding was not well covered in antenatal classes. 
  • Lack of professional support – women experienced difficulty in trying to establish breastfeeding but were unwilling ‘to bother the midwife’. Bottle feeding seemed easier. 
  • Experience – breastfeeding seemed difficult and painful, and many women experienced problems ranging from getting the baby latched on, sore nipples, and disturbed sleep. Women, especially adolescents, complained of a lack of freedom to travel/socialise/work. 
  • Worry about baby’s weight gain – women said that health visitors were ‘always worried about weight gain’.

Although some women in this study mentioned the benefits of breastfeeding – including feelings of wellbeing and relaxation during feeds, convenience (less washing up), and less expense, it is clear that there are significant barriers for women in the UK which impact on their choice to breastfeed. 

Source: McFadden A & Toole G (2006) Exploring women’s views of breastfeeding: a focus group study within an area with high levels of socio-economic deprivation. Maternal & Child Nutrition 2: 156-68.

For further information about healthy food for babies and children, please come to a Cooking for Health course led by nutrition expert, Dr Jane Philpott.

Infant feeding affects obesity in later life

Three decades ago, it was proposed that disease risk in human adults may be programmed by environmental influences acting on hormones, metabolites and neurotransmitters, during sensitive periods of early development.  Since then, much supporting evidence for this hypothesis has accumulated from epidemiologic and experimental studies and clinical trials.  For example, numerous studies have reported programming effects of infant feeding choices on later obesity.  Three meta-analyses of observational studies found that obesity risk at school age was reduced by 15 to 25 per cent with early breastfeeding compared with formula feeding. 

A new paper in the American Journal of Clinical Nutrition reports on investigations into whether breastfeeding protects against later obesity by reducing the occurrence of high weight gain in infancy.  One reason for this may be the lower protein content of human milk compared with most infant formula (the early protein hypothesis).

Researchers are testing this hypothesis in the European Childhood Obesity Project, a double-blind, randomized clinical trial that includes >1000 infants in 5 countries (Belgium, Germany, Italy, Poland, and Spain).

Healthy infants who were born at term were randomly assigned to receive for the first year infant formula and follow-on formula with higher or lower protein contents, respectively. The follow-up data obtained at age 2 y indicate that feeding formula with reduced protein content normalizes early growth relative to a breastfed reference group and the new World Health Organization growth standard, which may furnish a significant long-term protection against later obesity.

Researchers conclude that infant feeding practice has a high potential for long-term health effects, and the results obtained should stimulate the review of recommendations and policies for infant formula composition.

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It is interesting that the authors do not also suggest public health action to encourage higher rates of breastfeeding. 

All current guidelines, including those from the Department of Health (DH), recommend exclusive breastfeeding for newborns and for the first six months of infancy.

Breast milk provides all the nutrients required at this age in a form that is hygienic and easy to digest. The protein, carbohydrate and fat profiles are unique to breast milk and differ in many ways from other animal milks.  Breast milk also contains a range of bioactive components, including anti-microbial and anti-inflammatory factors, digestive enzymes, hormones and growth factors.  Growth factors are thought to be important for gut maturation. Lactoferrin is one of several specific binders in human milk that greatly increase the bioavailability of micronutrients.

The role of leptin in breast milk may be of particular importance in the early development of both adipose (fatty) tissue and appetite regulatory systems in the infant, and ultimately on propensity to obesity in later life.

Despite the many benefits of breastfeeding, less than 1 per cent of women in the UK are still breastfeeding at 6 months.  Studies have shown that women in the UK experience substantial barriers to breastfeeding.

For further information about healthy food for your children, please come to a Cooking for Health course, led by nutrition expert Dr Jane Philpott.

Alzheimer’s Disease, metabolic disorders and the role of diet

Accumulating evidence for the role of metabolic disorders such as insulin resistance, diabetes, obesity and hypertension in increasing the risk of Alzheimer’s disease and vascular dementia, is reviewed in a new paper published this month in the Archives of Neurology.

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In the same journal, compelling evidence is presented that higher pre-diagnosis total cholesterol, low-density lipoprotein cholesterol, and diabetes are associated with faster cognitive decline in patients with incident Alzheimer’s disease.

A cohort of 156 patients with incident Alzheimer’s Disease (mean age 83 years) were followed for up to 10 years.  Changes in a composite score of cognitive ability were monitored from diagnosis onwards.

“These findings indicate that controlling vascular conditions may be one way to delay the course of Alzheimer’s, which would be a major development in the treatment of this devastating disease as currently there are few treatments available to slow its progression,”

said Yaakov Stern, Ph.D., a professor at the Taub Institute for the Research on Alzheimer’s Disease and the Aging Brain and director of the Cognitive Neuroscience Division of the Gertrude H. Sergievsky Center at Columbia University Medical Center, and senior author of the paper.

“Preventing heart disease, stroke and diabetes – or making sure these conditions are well managed in patients diagnosed with them – can potentially slow the disease progression of Alzheimer’s,” said Dr. Stern.

Diets high in fruit, vegetables, fibre and unsaturated fats, and low in sugar, salt and saturated fat are known to reduce the risk of a range of chronic conditions, such as diabetes, heart disease and stroke.  This means eating more plant-based foods and less processed and animal-based foods.

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Stabilising blood sugar is crucial.  This may be done by eating a diet with a low glycaemic load, that is, one that includes moderate quantities of complex carbohydrates which release glucose slowly into the bloodstream.  Whole grains, such as whole-wheat bread, brown rice, quinoa, millet and buckwheat are valuable for helping to ensure smooth regulation of blood sugar.  In contrast, highly refined carbohydrates, such as white bread, white rice, white pasta and table sugar, create a roller-coaster of blood sugar highs and lows, which if left unchecked, can ultimately give rise to insulin resistance and eventually to diabetes.  Potatoes release sugar into the bloodstream almost as fast as table sugar and thus should be eaten sparingly, unless you are lean and exercise regularly.  Consuming protein with carbohydrates at every meal has also been found to help regulation of blood sugar.

Increasing the quantity of vegetables and fruit in the diet is also vital.  Blood sugar levels are easier to maintain if vegetables are emphasized more than fruit, as some fruit contains a lot of sugar.  A minimum of 5 portions of fruit and vegetables per day is recommended.  For easy tips for increasing the amount of fruit and vegetables in your diet please click here.

Unsaturated fats found in plant oils, such as olive oil and the oils of nuts and seeds, and in oily fish, are beneficial for preventing heart disease and other vascular health conditions.  For practical suggestions for ways to incorporate more healthy unsaturated fats in your diet please click here.

For information and practical tuition in how to put all these recommendations together to create fabulous food that protects you from diabetes, heart disease and Alzheimer’s Disease, please come to a Cooking for Health course, run by nutrition expert, Dr Jane Philpott.

Long term health is affected by maternal nutrition

This month, the British Medical Association (BMA) Board of Science has published a report on Early Life Nutrition and Lifelong Health.  The report reviews the evidence that the diets of women of reproductive age, and those of their foetuses and young children, are significant factors in influencing the risk of chronic diseases such as heart disease, diabetes, obesity, brittle bone disease and even some forms of cancer and mental illness, later in those children’s lives.

Lead author Professor Mark Hanson, director of the Centre for the Developmental Origins of Health and Disease at the University of Southampton, comments:

“Society and public health organisations need to pay much greater attention to these issues if the rising epidemic of these diseases is to be prevented. Tackling the diseases once children reach adulthood is often too late. By taking steps to improve maternal nutrition we could save many people from a lifetime of ill health.”

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Unbalanced nutrition can result from both inadequate and excessive dietary intakes, and both can exist at the same time in many populations. Moreover diets which lead to over-nutrition (e.g., excess calories) are often micronutrient poor.

There is strong evidence that undernutrition (stunting or wasting) during the first two years of life leads to impaired adult cognitive, physical and economic capacity, which cannot be repaired even if nutrition improves later in childhood.

Improved availability of energy-rich foods has however, enabled large numbers of people to escape from hunger. This has brought considerable benefits, but is already giving rise to obesity and obesity-related disease. Developing countries are reporting high rates of coronary heart disease (CHD) and type 2 diabetes that have appeared in one or two generations to become leading causes of morbidity and mortality. These epidemics are expected to intensify.  By the year 2030, the prevalence of diabetes is predicted to rise by over 100 per cent in India, China, sub-Saharan Africa, Latin America, the Caribbean and the Middle East; an increase far exceeding that in high-income countries (54%).

There is good evidence that an increased deposition of fat tissue in foetuses and babies is an outcome of both undernutrition and excessive nutrition.  Low birth weight babies born to underweight women in India have proportionately more fat than would be expected for their body weight.  Maternal obesity, another form of maternal malnutrition, also increases the fat tissue of the foetus and newborn baby. This phenomenon is exacerbated further if maternal obesity is complicated by gestational diabetes.

Extremes of maternal body composition, either excessive thinness or obesity, are associated with adverse patterns of foetal and infant development leading to poorer long-term health.

“It’s not only women who need to be careful about the quality of their food intake. Prospective fathers should also eat well and steps need to be taken to ensure that young people understand the importance of good nutrition as part of their lifestyle choices.”

The numbers of women who breastfeed their infants is still too low, with many women starting to breastfeed but then stopping too soon, and many infants being fed inappropriate foods at the weaning stage.  Breastfeeding rates in the UK are much lower than in many European countries. Less than1 per cent of mothers in the UK are exclusively breastfeeding at six months.

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While there are gaps in the evidence about the long-term consequences of poor maternal and infant nutrition, and we do not as yet understand the mechanisms fully, it is clear that steps need to be taken to promote healthy diets in young women and their families, to encourage breastfeeding and the use of appropriate complementary foods.

More advice could be given to people with young children about the importance of a balanced diet for those children and more support could be given to women to help them start breastfeeding and to continue with it.

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Fruit and vegetable consumption low across the world

eating-burger_280_528732a1A new study to be published in the May edition of the American Journal of Preventive Medicine paints a depressing picture of the dietary habits of modern man across the globe.

National Diet and Nutrition Surveys in the UK have found that less than 15 per cent of the population eats the recommended 5 portions of fruit and vegetables per day; a similar situation exists in the USA.  It appears that the same is also true in developing countries, where traditional diets are threatened by the introduction of processed food.

A survey of over 200,000 people in developing countries showed that overall 77.6 per cent of men and 78.4 per cent of women consumed less than the suggested five daily servings of produce. 

“Low fruit and vegetable consumption is a risk factor for overweight and obesity, and adequate consumption decreases risk for developing several chronic diseases,” said lead author Spencer Moore. “The release of the 2002-2003 World Health Survey data provided a unique opportunity to examine global differences in low fruit and vegetable consumption in a way that has until now simply not been possible.”

There were wide variations among nations, ranging from 37 percent of men in Ghana who did not meet that standard – to 99 percent of Pakistani men. The researchers saw similar findings in women with the same two countries at the high and low ends of the spectrum.

The prevalence of low fruit and vegetable intake increased with age and decreased with income. This contrasts with findings from the UK where, on average, older people consume more fruit and vegetables than younger people.

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Epidemiological studies show that societies consuming high quantities of fruit, vegetables and whole grains are at lower risk of developing chronic diseases such as diabetes, heart disease and cancers than those that consume low quantities.  Such societies are often, but not exclusively, in less economically developed parts of the world.  As GDP per capita increases, countries opt for eating more meat, more processed food and less fruit, vegetables and whole grains.  This dietary shift leads to an epidemiological shift – away from infectious diseases and other diseases associated with lack of food, towards chronic noncommunicable diseases such as heart disease, stroke and cancer. 

The decline in consumption of fruit and vegetables in developing countries is disturbing as it is likely to give rise to an increase in the incidence of chronic diseases, leading to huge burdens on the healthcare systems of those countries, which may be ill-equipped to cope.

For information and practical tuition in how to create mouth-watering dishes with locally produced fruit and vegetables, come along to Cooking for Health courses held throughout the year in Somerset, UK.

If you are a caterer, or a professional responsible for encouraging healthier catering practices in your community, you will benefit from participating in a two-day training course on Healthier Catering.   By the end of the course, participants will: 

  • Understand the basic principles of nutrition
  • Be aware of the importance of food in the maintenance of health and well-being
  • Appreciate the role of lifestyles and culture in influencing diet
  • Recognise the potential benefits for both caterers and customers of providing a choice of healthier options
  • Know more about ingredient selection and methods of food production and processing that can be used to create healthier options, whilst being attractive and convenient to modern tastes and lifestyles
  • Be able to apply appropriate and relevant skills and knowledge when advising catering businesses or when planning, preparing, promoting and serving healthier foods

For further details about the course content and the course tutor, Dr Jane Philpott, please see http://cookingforhealth-uk.com/healthier-catering.php.

Reference

Hall JN, et al. Global variability in fruit and vegetable consumption. Am J Prev Med. 36(5), 2009.