Tuesday, October 20, 2015

DOES RED MEAT CAUSE CANCER? (Mr Roger Leicester)

With so much focus once again on red meat and cancer, it’s time to dust off SACN’s 2010 Iron and Health report [1] and put things back into perspective.

An exhaustive review of the literature in 2010 by the government’s Scientific Advisory Committee on Nutrition (SACN)[2]  concluded that eating up to 70g of red meat daily does not pose a risk for colorectal cancer. SACN noted difficulties in interpreting the inconsistent evidence base saying: “it is not possible to quantify the amount of red and processed meat that may be associated with increased colorectal cancer risk because of limitations and inconsistencies in the data”.

In fact there is no evidence showing that lean, red meat has any causal relationship with the initiation of cancers.

Avoiding red meat in the diet is not a protective strategy against cancer.  Results from many studies show a very weak association between high red meat consumption and increased risk of cancer.  These include the large EPIC study, of which there is a British cohort, has found similar rates of bowel / colorectal cancer in vegetarians and meat-eaters [3].  Other studies have also shown no association between red meat intake and risk of other types of cancer including prostate [4], and breast cancer [5].

Many studies have attempted to show a link between red meat consumption and cancer but many are poorly designed, using food frequency questionnaires and lacking the use of urinary biomarkers as indicators of red meat intakes.  In fact, the interdependency of food consumption with other dietary and lifestyle factors, socioeconomic characteristics, clinical variables, and genetic traits makes it difficult to isolate the independent effects of a specific food or food group, such as meat intake, on disease risk.

Cancer specialist, Professor Karol Sikora has noted that those people who enjoy eating red meat should continue to do so; he adds: "We have created a nightmare situation of confusing messages based on very little evidence. Eating red meat in the context of a balanced diet should really not be viewed as a problem. Yes, avoid a high calorie, high fat diet - but by all means enjoy that steak.”

Follow the SACN guidance
Instead of the knee jerk reaction of eating less red meat, we have excellent guidance from SACN which advises that people who eat more than 90g red meat daily should lower their intakes to an average of 70g. Given changes to meat consumption over the past decade, average intakes are now 71g suggesting that most people don’t need to change their meat consumption.



References
[2] SACN (Scientific Advisory Committee on Nutrition) (2011). Iron and Health. http://www.sacn.gov.uk/pdfs/sacn_iron_and_health_report_web.pdf
[3] Keys T et al. (2014) Cancer in British vegetarians: updated analyses of 4998 incident cancers in a cohort of 32,491 meat eaters, 8612 fish eaters, 18,298 vegetarians, and 2246 vegans. Am J Clin Nutr 100(suppl): 378S–85S.
[4] Rohrmann, S., et al. (2015). "Intake of meat mutagens and risk of prostate cancer in a cohort of U.S. health professionals." Cancer Epidemiol Biomarkers Prev.   
[5] Alexander, D et al (2010)” A review and meta-analysis of red and processed meat consumption and breast cancer.” Nutr Res Rev 23(2): 349-365

Friday, October 16, 2015

NITRATES, NITRITES AND BOWEL CANCER - (Professor Robert Pickard)

Much of the advice about red meat in the diet refers to unprocessed lean red meat but what about processed meat? Can we still eat it? And what’s the deal with nitrates and nitrites?

Let’s look at processed meat first. Processed meat is defined [1] as “meat preserved by smoking, curing, salting, or the addition of preservatives. This includes, for instance, ham, bacon, salami, and some sausages such as frankfurters.” Processed meat differs from fresh meat as it tends to be higher in salt and can contain preservatives added during the curing process which slow down the meat spoilage and reduce microbiological risks. You simply can’t make bacon and salami without them.

So what about nitrates and nitrites? 80% of dietary nitrates come from vegetable consumption and there is evidence that some sources of these in the diet support normal blood pressure [2].  Nitrites and nitrates are used to preserve cured meats – you can’t preserve the meat without them. Salt has also been used to preserve meat for generations.

The prime reason to use such additives is the need to protect us against the microbe Clostridium botulinum.  This bacterium produces a virulent toxin and the risk of death from botulinum is a very real public health issue.  Recent research has also documented that nitrite used in processed meat products significantly reduces growth of Listeria monocytogenes.

There are theories, mainly based on animal studies, that overcooking meat, or changes in meat due to preservation, could explain links with bowel cancer but there is no consensus on this.  In fact, an exhaustive review of the literature in 2010 by the government’s Scientific Advisory Committee on Nutrition (SACN) [3] concluded that eating up to 70g of red meat daily was consistent with normal health and adequate iron status. SACN noted difficulties in interpreting the inconsistent evidence base saying: “it is not possible to quantify the amount of red and processed meat that may be associated with increased colorectal cancer risk because of limitations and inconsistencies in the data.”

In fact, if you were going to prevent bowel cancer, the strongest evidence is for tackling smoking, alcohol, obesity and physical inactivity.


References
[2] Hord NG et al. (2009) Food sources of nitrates and nitrites: the physiologic context for potential health benefits. Am J Clin Nutr 90: 1-10.
[3]SACN (Scientific Advisory Committee on Nutrition) (2011). Iron and Health. http://www.sacn.gov.uk/pdfs/sacn_iron_and_health_report_web.pdf

ARE VEGETARIAN DIETS REALLY BETTER FOR HEALTH? (Dr Emma Derbyshire)

It’s perfectly possible to eat healthily on a vegetarian or vegan diet, followed by 2-4% of the population, but this requires good planning and cooking skills as well as access to alternative sources of animal-based nutrients.

Studies show that vegetarian diets can be low in zinc, calcium, iron, manganese, selenium, and copper [1]  while vegetarians and vegans often have lower intakes of vitamin D [2, 3], and long-chain omega-3 fatty acids [4]. Vitamin B12, which is required for healthy nerves and red blood cells, can be a major issue for vegans as this nutrient is only present in foods of animal or microbiological origin [5].

Vegetarians tend to be healthier than the rest of the population thanks to the combined effect of lower body mass index, more exercise, lower smoking prevalence and higher intakes of fruit, vegetables and fibre. Meat eaters can also achieve optimal health by choosing lean cuts of red meat and aiming for at least 5-a-day fruit and vegetables, as well as whole grain foods, low fat dairy products, and oily fish once a week.

As studies show that lean red meat performs just as well as carbohydrate or other protein sources in terms of blood pressure [6], body fat [7,8], glucose levels [9], and blood lipids [10],  you can still enjoy red meat during your health kick.











References
[1] Freeland-Grave-J (1988) Mineral adequacy of vegetarian diets. The American Journal of Clinical Nutrition  48:859-62
[2] Calvo Ms, Whiting SJ, Barton CN (2005) Vitamin D intake: a global perspective of current status. Journal of Nutrition 135 310-6
[3] Laskowska-Kilta T, Chelchowska M, Ambroszkiewicz J, Gajewska J, Klemarczyk W (2011) The effect of vegetarian diet on selected essential nutrients in children 15:318-25
[4] Welch AA, Shakya-Shrestha S, Lentjes MA, Wareham NJ, Khaw KT (2010) Dietary intake and status of n-3 polyunsaturated fatty acids in a population of fish-eating and non-fish-eating meat-eaters, vegetarians, and vegans and the product-precursor ratio [corrected] of a-linolenic acid to long-chain n-3 polyunsaturated fatty acids: results from the EPIC-Norfolk cohort. The American Journal of Clinical Nutrition (2:1040-51
[5] Ambroszkiewicz J, Klemarczyk W, Chelchowska M, Gajewska J, Laskowska-Klita T (2006) Serum homocysteine, folate, vitamin B12 and total antioxidant status in vegetarian children. Advances in medical science 51:265-8
[6] Hodgson JM et al. (2006) Partial substitution of carbohydrate intake with protein intake from lean red meat lowers blood pressure in hypertensive persons. Am J Clin Nutr 83: 780-7.
[7] Noakes M et al. (2005) Effect of an energy-restricted, high-protein, low-fat diet relative to a conventional high-carbohydrate, low-fat diet on weight loss, body composition, nutritional status, and markers of cardiovascular health in obese women. Am J Clin Nutr 81: 1298-306.
[8] Noakes M et al. (2005) Effect of an energy-restricted, high-protein, low-fat diet relative to a conventional high-carbohydrate, low-fat diet on weight loss, body composition, nutritional status, and markers of cardiovascular health in obese women. Am J Clin Nutr 81: 1298-306.
[9] Turner KM et al. (2015) Red meat, dairy, and insulin sensitivity: a randomized crossover intervention study. Am J Clin Nutr 101: 1173-9.
[10] Davidson MH et al. (1999) Comparison of the effects of lean red meat vs lean white meat on serum lipid levels among free-living persons with hypercholesterolemia: a long-term, randomized clinical trial. Arch Intern Med 159: 1331-8.

HOW MUCH PROTEIN DO WE NEED? (Dr Carrie Ruxton)

I’ve been working out a lot this year in order to take part in the 105 mile Coast to Coast challenge; a two day event in September involving running, cycling and kayaking across Scotland. It was hard but I recovered well thanks to a good amount of high quality protein in my diet.
We are often told that we eat too much protein in developed countries but this really depends on your age and how much exercise you do. Yes, average intakes are above general recommendations of around 55g per day but two groups in particular need more than that; elderly folk and people taking part in regular exercise.

Studies show that, once we hit 50 years of age, our muscle mass begins to decline. This increases the risk of sarcopenia which, in later life, causes muscle wasting and may exacerbate falls. High quality protein, such as that found in red meat, helps to maintain muscle size and strength particularly when combined with resistance training[1] .

In fact, the evidence for protein’s important role in muscle function is so compelling it has been recognised by European regulators. These watchdogs have rejected hundreds of health claims but have given the approval to the statement that protein “contributes to a growth in muscle mass”.

Any food or drink which provides at least 12% of its energy from protein — as almost all red meat does [2]  — is authorised to include this important health message on packaging and marketing materials. Some cuts, such as lean rump (18%) or pork chops (20%) contain an even higher percentage of energy in the form of protein [3].

Fitness fans can also benefit from slightly more protein, especially after training sessions to help support muscle recovery. In my new review in Complete Nutrition [4] , I discuss international protein recommendations for sports enthusiasts and explain how high protein foods, such as red meat, contribute to optimal performance.






References
[1] Goisser et al. (2015) Sarcopenic obesity and complex interventions with nutrition and exercise in community-dwelling older persons--a narrative review. Clin Interv Aging 10: 1267-82.
[2] http://meatandhealth.redmeatinfo.com/media/old/Red%20meat%20and%20protein.pdf
[3]
http://meatandhealth.redmeatinfo.com/media/old/Red%20meat%20and%20protein.pdf 

Calculation for rump example: 100 divided by 176 (cals) multiplied by 31.2 (protein per 100g) equals 17.7, rounded up to 18%
[4] Ruxton C & Cobb R (2015) Benefits of protein for sport and exercise. Complete Nutrition in press.
 
 
 


COLORECTAL CANCER – THE FACTS (MR ROGER LEICESTER)

Bowel cancer is now the third most common cancer in the UK but our cancer screening methods have really moved on and as a result we are able to diagnose many more cases than ever before.

The much repeated view from meat-free campaigns and animal charities is to eat less red meat but the evidence doesn’t stack up. In fact there is no evidence showing that lean, red meat has any causal relationship with the initiation of cancers.

Avoiding red meat in the diet is not a protective strategy against cancer.  Results from many studies show a very weak association between high red meat consumption and increased risk of cancer.  These include the large EPIC study, of which there is a British cohort, has found similar rates of bowel / colorectal cancer in vegetarians and meat-eaters [1].  Other studies have also shown no association between red meat intake and risk of other types of cancer including prostate [2], and breast cancer [3].  

In fact, Bowel Cancer UK states the main risks for bowel cancer as age, gender and family history than diet and lifestyle [4].
Keeping healthy is vital and as a result I advice patients the following:
• Eat at least 5 portions of fruit and vegetables daily if not more
• Take regular exercise – half an hour a day is a good starting point as per WHO guidelines
• Aim for an average of 70g cooked red meat daily as per SACN guidelines
• Eat plenty of high fibre and wholegrain foods.






References
[1] Keys T et al. (2014) Cancer in British vegetarians: updated analyses of 4998 incident cancers in a cohort of 32,491 meat eaters, 8612 fish eaters, 18,298 vegetarians, and 2246 vegans. Am J Clin Nutr 100(suppl): 378S–85S.
[2] Rohrmann, S., et al. (2015). "Intake of meat mutagens and risk of prostate cancer in a cohort of U.S. health professionals." Cancer Epidemiol Biomarkers Prev.   
[3] Alexander, D et al (2010)” A review and meta-analysis of red and processed meat consumption and breast cancer.” Nutr Res Rev 23(2): 349-365
[4] www.bowelcanceruk.org.uk/understanding-bowel-cancer/risk-factors/

DON’T FORGET ABOUT IRON (Dr Carrie Ruxton)

Last year I felt tired and lethargic and struggled to catch my breath when I climbed the stairs. I was amazed on giving my usual blood donation to discover that I was iron deficient, particularly as I eat red meat. A few months later, everything was back to normal thanks to more focus on my diet. But, it made me more aware about iron deficiency which remarkably affects one in ten women in the UK.

Everyone thinks of Popeye and spinach in relation to iron but red meat is, in fact, the best available dietary source. The haem iron in red meat is two to six times better absorbed than the non-haem iron found in pulses, green vegetables and fortified foods. Haem iron also boosts the absorption of non-haem iron making it a good idea to serve a large portion of broccoli with your steak!

Those at particular risk of low iron intakes and poor iron status are women, teenagers, athletes and people who avoid or eat very little red meat. A few dietary considerations can make all the difference such as eating red meat 4-5 times a week (up to 500g cooked weight per week), drinking a glass of orange juice with meat meals, serving green leafy vegetables with main meals, and eating fortified breakfast cereals.

HEALTHY EATING AND RED MEAT (Dr Gill Jenkins)

More than nine out of ten people in the UK eat meat, making it one of our staple foods. The Eatwell Plate includes red meat within the protein section while studies show that red meat is a good source of B vitamins, iron, zinc, potassium and selenium [1]. Red meat even contributes around a fifth of our vitamin D intake in the UK and is the most bioavailable source of iron and zinc in the diet.

All these nutrients come in a healthier package as red meat is now up to 30% lower in fat than it was in the 1950s. This is due to improvements in animal breeding and feeding, as well as more skilful butchers. Grilled sirloin steak now contains less than 8% fat while roast pork leg contains less than 6% fat [2]. Surprisingly, a 100g portion of cooked red meat is less than 200 calories while a similar amount of grilled salmon would be 240 calories.

By following current advice on red meat consumption – up to 500g cooked weight per week – we can benefit from the rich protein and nutrient content of red meat while keeping intakes in balance with other helpful foods.








References
[1] Ruxton CHS et al. (2013) Micronutrient challenges across the age spectrum: Is there a role for red meat? British Nutrition Foundation Bulletin, 38, 178-190.
[2] Calculated from McCance & Widdowson’s Composition of Foods.

CARCINOGENS – THE FACTS (Dr Carrie Ruxton)

If we believed everything that is said about carcinogens, we would hardly dare to breathe in, let alone eat food. While the world is full of carcinogens, the good news is that our bodies are designed to deal with the challenge. The risk comes with repeated exposure over time in those with a genetic predisposition. I saw this first hand when my grandmother developed lung cancer and, frustratingly, refused to give up her 20 a day habit. It has certainly alerted me to the dangers of smoking.

But when it comes to potential carcinogens in food, the links with cancer are less clear cut. To investigate the issue, researchers mainly use case control or cohort studies to follow up people over time and check who develops cancer and who stays healthy. Diets, often eaten decades in the past, are then compared to look for any differences. Neither type of study provides conclusive evidence that a particular food causes cancer, just that the variables are statistically linked. The next step of proof requires controlled studies, or research on human tissues to prove mechanisms, but these are in very short supply.

In the meantime, should we worry about the carcinogens that are reported to exist in cleaning products, pesticides, food, make-up, hair dyes and deodorants? No, because the crucial aspects for reducing cancer risks are how much exposure you have to carcinogens and over what length of time. This is why there are strict rules governing the levels of potentially carcinogenic substances that are allowed into foods and consumer products.

Wednesday, February 25, 2015

Red Meat and Heart Health

With over 160,000 deaths each year[1] attributed to cardiovascular disease (CVD), GP Dr Gill Jenkins, member of the Meat Advisory Panel discusses heart heath and takes a look behind the red meat headlines.

  • 7 million people are living with cardiovascular disease in the UK1
  • Nearly one in six men and one in ten women die from coronary heart disease1
  • There are up to 175,000 heart attacks in the UK each year, that’s one every three minutes1

“February is National Heart Month, a campaign by the British Heart Foundation, and is often a time when people may stop to think about their own heart health. Patients often ask me what type of things can have an impact on their heart and what steps they can take to look after it. Quite often they come to me with the latest media headlines about heart disease, asking for example if they should stop eating red meat.

“In terms of looking after our heart, we should be;

  • Following a healthy balanced diet, with 5 portions of fruit and veg a day and keeping your intake of fatty foods low.
  • Moving around and taking part in exercise – be it a walk or a gym class- its recommended to have 30minutes of activity (enough to make you mildly sweaty or mildly breathless), 5 days a week, although you can break this into smaller more frequent amounts.
  • Watching our weight – if you are overweight gradually reduce your portion sizes and gradually increase your activity levels to get slowly reduce your weight over several months.
  •  Not smoking – smoking has the greatest risk to your heart so seek help to stop, ask at your health centre to see the specialist nurse or doctor.
  • Not drinking too much alcohol.
  • Know your cholesterol level and how to reduce it, if it’s too high – again, ask at your health centre about having a test, and also about having your blood pressure checked.
“The latter part of the advice is easier for patients to understand what they need to do. It’s the healthy balanced diet that gets the questions.

Moderation and a little bit of everything
“I tell my patients that moderation and a little bit of everything is the key to good health. They often ask me about red meat and if they should stop eating it. No is the answer, lean meat has lots of health benefits. Lean red meat provides vital protein, plus vitamins and minerals to help fuel our body’s needs.

“This includes vitamin A for eye and skin health, vitamin D for bone health and immune function, iron for energy levels and cognitive function, magnesium for muscle and nervous function, zinc for reproductive health, hair and nails, and selenium, which acts as a powerful antioxidant and potassium for blood pressure control.

“With regards to headlines suggesting people stop eating red meat, results from the Atherosclerosis Risk in Communities (ARIC) study did not indicate any association between total red meat intake and randomisation for heart failure.[2]

“The Scientific Advisory Committee on Nutrition (SACN) recommends average daily red meat intake of up to 70 grams per day (as cooked meat)  for adults[3].  Average intakes in the UK are already close to this level at 72g daily, suggesting that most people do not need to eat less red meat.”




[1] https://www.bhf.org.uk/~/media/files/research/heart-statistics/cardiovascular-disease-statistics---headline-statistics.pdf
[2] Nettleton JA, Steffen LM, Loehr LR, Rosamond WD, Folsom AR. Incident heart  failure is associated with lower whole-grain intake and greater high-fat dairy and egg  intake in the atherosclerosis risk in communities (aric) study. J Am Diet Assoc. 2008;108:1881-1887.

[3] SACN (Scientific Advisory Committee on Nutrition). (2010). "Iron and Health."   http://www.sacn.gov.uk/pdfs/sacn_iron_and_health_report_web.pdf

Tuesday, February 24, 2015

Modern diets are out of step with our evolutionary needs - Dr Carrie Ruxton

“I recently authored a study on behalf of the Meat Advisory Panel, published in Complete Nutrition, outlining how foods which were rarely, or never, eaten by our ancestors now account for 70% of our daily energy intake.


“Questions which can be drawn from this is to ask if our modern eating habits are actually powering an epidemic of obesity and diet-related diseases, such as cancer and cardiac problems and what would happen to this crisis if we returned to a more ancestral, paleo-type diet.


“Genetically we are still stone-age hunter-gathers who flourish on a diet of lean meat, fruit, vegetables and nuts, but in this day and age we are surrounded by foods laden with sugar, simple carbohydrates and the wrong type of fats – all within easy reach.


“If we take a look at the fossil record and diets of contemporary hunter-gatherer societies, it suggests that we are actually best suited to a diet which is higher in protein, omega-3 fatty acids, monounsaturated fats and fibre, but lower in carbohydrates, omega-6 fatty acids and saturated fats, and devoid of refined sugars.


“Often red meat gets the blame as being a risk factor in cardiovascular disease, but in fact modern hunter-gatherers eat far more red meat than is recommended in Western countries, yet have a far lower risk of cardiovascular conditions.


“If we take a leaf out of our ancestor’s book and follow protein-rich eating regimes, which includes a moderate amount of red meat, such as the Paleo diet, we could be benefiting from countless health benefits.

"As a result of this research, I developed a five-point plan which highlights the benefits of a paleo-type diet and suggests simples swaps to eat for your evolutionary age." 


Paleo diets

Nutrient/

health impact

Modern equivalents

High intakes of game meat

High intakes of MUFA, PUFA, lower SFA. High intakes of protein

Choose lean red meat and game, remove any visible fat and cook without extra fat, or use olive oil

Low intakes of processed carbohydrates and modern grains

Lower carbohydrate content and lower GL than modern diets. More dietary variety from gathered grains

Include a wider range of wholegrains in the diet e.g. rye, spelt, barley, flax, teff (ancient grain)

Use of honey and fruits to sweeten

Reduced added sugar consumption, lower GI

Honey and fruits can still be used to sweeten

Foraged marine foods

High intakes of n3PUFA and vitamin D

Consume fish twice a week, including one portion of oily fish. Consume shellfish and molluscs

Wide variety of foraged plant foods

High intakes of fibre and PUFA

Snack on nuts and seeds. Choose a wider variety of vegetables
 
 



 [i1]Are we suggesting that others adopt this 5 point plan… is the aim to help other HCPs spread this news of what we should and should not be eating?

Friday, February 13, 2015

How much red meat should we be eating?

Guest dietitian from the Meat Advisory Panel, Dr Mabel Blades advises how much red meat should be included in a healthy, balanced diet:
“I quite often get asked how much red meat we should be eating and what the recommended weight actually looks like on the plate. To start with the guidelines,  the Scientific Advisory Committee on Nutrition (SACN) recommends that adults should eat a balanced diet with up to 500g (cooked weight) of lean red meat a week or up to 70g per day.

“So, we have clear government guidelines but what does 70g of red meat actually look like on your dinner plate?
“When meat is cooked it loses about a third of its raw weight due mainly to losing water. If you dry fry 100g raw minced beef it will, after cooking, be approximately 70g in weight. This is always a useful guide when buying meat as you can ask the butcher for 100g per person of raw meat or look for packs in the supermarket of the appropriate size.”

Examples of approximately 70g portions of cooked meats and meat products include:

• One medium portion shepherd’s pie, lasagne, cottage pie, stir fry, chilli or any dish where you normally use lean minced meat
• One lamb chop
• Two slices of roast lamb, beef or pork
• A piece of rump or sirloin steak about the size of a pack of cards
• Three grilled lean rashers of bacon
• 2 large or 3 small grilled sausages
• Two standard beef burgers or one quarter pounder
• Three slices of ham

“So why should we be including lean red meat in our diets? Well, beef, pork and lamb contribute to the all-important balance that necessary for a healthy diet and this is backed by the Department of Health. It highlights that red meat is a good source of protein, and vitamins and minerals such as iron, selenium, zinc and B vitamins.

“It is also one of the main sources of vitamin B12, which is only found in foods of animal origin, such as meat and milk.”