Friday, February 28, 2014

Why go meat-free when you can enjoy lean red meat in a healthy balanced diet?

Dr Carrie Ruxton, registered Dietitian and member of the Meat Advisory Panel

There’s an increasing number of so-called ‘awareness’ weeks and months encouraging us to turn to a vegetarian or vegan diet. Often these campaigns vilify meat, and more often than not incorrectly link red meat as a cause for health conditions.  Should we all be jumping on the bandwagon and turning vegetarian, or is it a better option to follow a healthy balanced diet made up of a number of food sources?

 Vegetarian diets are currently followed by 2 - 4% of the population, but if we take a moment to look at ourselves; we are omnivores – historically and physically. We are not designed to digest cellulose like naturally vegan animals, such as cows, rabbits and sheep.  

 In terms of health, choosing to follow a vegetarian, or vegan, diet is a lifestyle choice, it is not vital for health as some may suggest.  In fact, any choice that restricts eating habits, such as a meat-free diet, brings with it a risk of inadequate intake of nutrients.

 Studies have shown that vegetarian diets can be low in zinc, calcium, iron, manganese, selenium, and copper[1]. Vegan and vegetarian diets can restrict vitamin D intake[2],[3] and following these types of diets greatly reduce intakes of long-chain omega-3 fatty acids[4]. Another key nutrient, vitamin B12 is a major issue in vegans as this nutrient is only present in foods of animal or microbiological origin[5].

 While iron is present in some vegetables, beans and pulses, and fortified foods, it is of the non-haem variety which is poorly absorbed - only 10% of non-haem iron is absorbed compared with 30% of haem iron from red meat[6]. In addition, the presence of haem iron in foods increases the absorption of non-haem iron. Therefore, red meat is irreplaceable as a source of bioavailable iron in the diet.

With reference to red meat and health conditions, the evidence is inconsistent and research usually depends on observational studies which do not allow conclusions about ‘cause and effect’[7]. In many cases, studies combine fatty meat pies and pastries with lean red meat, and most do not account for differences in fibre intakes. Indeed, other studies have not found associations between red meat and cancer[8], and rates of bowel cancer are similar in meat eaters and vegetarians[9].

 Including red meat in the diet offers an array of nutritional benefits and helps us, as omnivores, achieve our recommended intakes of vitamins and minerals. We should be aiming to eat up to 70g of cooked lean red meat per day and up to 500g per week[10]which is beneficial for our overall health.



[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 92:1040-51
[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] SACN (2010). Iron and health. London: The Stationery Office. Available at: www.sacn.gov.uk/pdfs/sacn_iron_and_health_report_web.pdf
[7] Wyness L et al. (2011) Red meat in the diet: An update. Nutrition Bulletin 36: 34-77.
[8] Alexander DD et al. (2011) Meta-analysis of prospective studies of red meat consumption and colorectal cancer. European Journal of Cancer Prevention 20: 293-307.
[9] Key TJ et al. (2009) Cancer incidence in vegetarians: results from the European prospective investigation into cancer and nutrition (EPIC-Oxford). American Journal of Clinical Nutrition 89: 1620S–6S.
[10] SACN (2010). Iron and health. London: The Stationery Office. Available at: www.sacn.gov.uk/pdfs/sacn_iron_and_health_report_web.pdf


 

Thursday, February 6, 2014

Why does fat get a bad name ?

Dr Carrie Ruxton, registered dietitian and member of the Meat Advisory Panel

Since the 1970s, dietary fats have been a major target of Government nutrition policy, with advice to lower fat intake making a regular appearance in dietary initiatives. Yet current science seems to indicate that not all fats are equal, suggesting that our rather negative view of dietary fats needs to be updated.

Fats can be grouped into two different ‘families’ called saturated and unsaturated fats. Within these, there are several categories of fatty acids, as shown below:
  • Saturated fats: mainly from animal foods, such as dairy products, chocolate and meat products (pies and pasties), but also from some plant foods, such as coconut
  • Omega-3 polyunsaturated fats: mainly from oily fish, eggs, red meat, nuts, seeds and marine oil supplements
  • Omega-6 polyunsaturated fats: mainly from vegetable oils, such as sunflower oil and rapeseed oil, poultry, eggs, avocado and nuts
  • Omega-9 polyunsaturated fats: mainly from olive oil, rapeseed oil and nut oils.
Traditionally, saturated fats were viewed as ‘bad’ while unsaturated fats were viewed as ‘good’. This was informed by people -based studies which suggested associations between high intakes of saturated fat and an increased risk of heart disease. However, this opinion has been challenged in recent years due to evidence that certain saturated fatty acids, such as myristic and palmitic acids, have a negative impact on blood cholesterol levels while others, such as stearic acid present in red meat, does not appear to affect cholesterol1 . This suggests that saturated fats behave differently in the body.

There is also debate from some nutrition commentators on whether saturated fat should be targeted at all in dietary recommendations due to the weak association between saturated fat consumption and mortality from cardiovascular disease. However, this view has not been accepted by Government experts and more evidence is needed.

In the meantime, it is wise to continue choosing lower fat, nutrient-rich foods which provide a variety of types of fatty acids in the diet. Lean red meat is a good choice as it is now lower in fat and calories thanks to changes in farming practices over the past few decades. In fact many people don’t realise that red meat, on average, contains more unsaturated than saturated fats. It also contains a range of fatty acids, including those from the beneficial omega-3 and omega-6 groups.

[1] Hunter JE, Zhang J, Kris-Etherton PM. Cardiovascular disease risk of dietary stearic acid compared with trans, other saturated, and unsaturated fatty acids: a systematic review. Am J Clin Nutr. 2010;91:46–63.