Naude CE, Schoonees A, Senekal M,Young T, Garner P,Volmink J.
A systematic review comparing low carbohydrate and isoenergetic balanced diets for reducing weight and cardiovascular risk has been published recently. The review evaluated all relevant clinical trials comparing low carbohydrate and balanced diets. The findings show that over 2 years, in overweight and obese people with and without diabetes, the two diets had similar effects on weight, and similar effects on risk factors for heart disease and markers of diabetes. A document summarising the key findings of the review is available for download at this link:
The SANHANES-1: Non-communicable diseases in South Africa
Suggested citation: Shisana O, Labadarios D, Rehle T, Simbayi L, Zuma K, Dhansay A, Reddy P, Parker W, Hoosain E, Naidoo P, Hongoro C, Mchiza Z, Steyn NP, Dwane N, Makoae M, Maluleke T, Ramlagan S, Zungu N, Evans MG, Jacobs L, Faber M, & the SANHANES-1 Team (2014) South African National Health and Nutrition Examination Survey (SANHANES-1): 2014 Edition. Cape Town: HSRC Press.
Prevalence of risk markers for non-communicable diseases
In the SANHANES-1 of 2012 25 532 individuals of all ages were interviewed, 12 025 had a physical examination by a medical doctor and 8078 provided a blood sample for laboratory analysis. High blood pressure was found among an important proportion of the study participants, with 30.9% reporting a family history of hypertension and 16.5% reported that they had high blood pressure. The physical examination revealed that 10.4% of the participants aged 15 years and older had a blood pressure in the range between 120-139/80-89 mmHg and a further 10.2% were hypertensive. Almost one-quarter of persons aged 15 years and older had high serum total and LDL-cholesterol, while almost half had an abnormally low HDL-cholesterol. Almost 20% had impaired fasting glucose and 9.5% were diabetic.
Lifestyle related risk factors
The prevalence of general obesity, based on body mass index was significantly higher in women than in men, with 24.8% of women being overweight and 39.2% obese. In line with these results, 68.2% of the women had a waist circumference that placed them at risk for metabolic disorders, such as hypertension and type 2 diabetes. If the results are compared with the 2003 SA Demographic and Health Survey, obesity among women increased from 27% to 39.2% over 9 years. About two-thirds of women were satisfied with their current weight, although 76.4% of South Africans perceived that they had a 'fat' body image. Furthermore 88% indicated that their ideal body image was 'fat' and only 14.6% of women reported that they attempted to lose weight.
A step-fitness test revealed that more than one-quarter of men and almost half of all women were physically unfit. Almost 20% of the study participants consumed a diet with a high fat score or a high sugar score, whereas more than a quarter had low fruit and vegetable intakes.
The SANHANES-1 team encouraged the Department of Health to address risk factors for non-communicable diseases at the home, workplace and community level. The Food Based Dietary Guidelines and guidelines relating to physical activity should be used in an educational campaign. Health care facilities and community health workers should be enabled to offer services to prevent and control non-communicable diseases. They recommended that a task force should be formed to address the clinical management of hypertension, hyperlipidaemia and glucose homeostasis.
Jeannine Baumgartner, Ph.D. in Nutrition; Centre of Excellence for Nutrition, North-West University (Potchefstroom Campus), Potchefstroom, South Africa
Reprinted with permission from Nursing Update
Fats form an essential part of a child's diet, however, it is not solely the amount of fat that requires attention, equally or even more important is the quality (type) of fat a child consumes.
Traditionally, fats have been considered mainly as a source of energy, and got a bad reputation for causing obesity and coronary heart disease.Even though energy supplied from fat is necessary for a child's normal growth and physical activity, fats are more than just a convenient source of energy.Dietary fats carry fat-soluble vitamins (e.g. vitamins A, D, E and K) from the food into the body, and some specific dietary fats are of critical importance fora child's physical healthas well as the developmentand function of the brain and eyes1.
Most dietary fats and oils contain a mixture of three types of fatty acids: saturated, monounsaturated and polyunsaturated fatty acids. Fats high in saturated fatty acids, such as animal fat (e.g. visible fat on meat, butter,dairy cream) and certain plant oils (e.g. coconut oil, palm oil, palm kernel oil), are often referred to as 'hard' fats, because they are solid at room temperature. Saturated fatty acids are present in all dietary fats and oils in different quantities. Humans have no nutritional need for saturated fats because the human body can produce them. Furthermore, a high dietary intake of saturated fats might increase the risk for cardiovascular disease2. Monounsaturated fatty acids found in olive oil, canola oil, avocado, nuts and meat can also be produced by the human body. Nevertheless, they are usually regarded as 'healthy' fats as several studies have found beneficial effects of dietary monounsaturated fats on blood lipids when replacing saturated fats. Polyunsaturated fatty acids can be categorized into two families, the omega-3 and the omega-6 fatty acids (also known as n-3 and n-6 fatty acids). The parent fatty acids of these families, alpha-linolenic acid (omega-3 family) and linoleic acid (omega-6 family) cannot be made by the human body and must be provided by the diet. Therefore, they are called "essential" fatty acids. Dietary sources of alpha-linolenicacid include green leafy vegetables, flaxseed oil, canola oil, soybean oil and walnuts. Linoleic acid is present in many vegetable oils, and found in high quantities in safflower oil, sunflower oil, poppy seed oil, grape seed oil and maize oil.The essential parent fatty acids alpha-linolenic acid and linoleic acid can be converted by the body into longer chain versions, such as eicosapentaenoic acid (EPA, omega-3 family), docosahexaenoic acid (DHA, omega-3 family) and arachidonic acid (ARA, omega-6 family). However, it was shown that this conversion is not very efficient in humans3. EPA and DHA are found mainly in (fatty) fish (e.g. pilchards, mackerel, salmon, sardines, snoek), while ARA can be found in all types of meat, eggs and dairy products including milk, cream, butter, cheese and yoghurt. Omega-6 fatty acidsare less likely to be lacking from a child's diet, thus more attention is required to increase the dietary intake of omega-3 fatty acids, particularly of EPA and DHA.
When ignoring its water content, the human brain consists of 60% fat. DHA and ARA are the most abundant types of fat found in this crucial organ. DHA and ARA are needed to maintain the brain's structure and function. Thus, it comes to no surprise that a good supply of these fatty acids during early life is essential, as the brain is developing and maturing until young adulthood. There is growing evidence that cognitive performance (such as learning, memory and problem-solving) and behaviour in children can be enhanced by the provision of omega-3 fatty acids through breast milk and omega-3 fatty acid-rich foods during early life4, 5. In fact, breast milk provides all the essential fatty acids, as well their longer chain products ARA and DHA6, and is considered to be the optimal method for infant feeding. However, the concentration of these important fatty acids in breast milk is influenced by the mother's diet. Thus, it is important that breast-feeding mothers consume a diet rich in omega-3 and omega-6 fatty acids. Once the transition to solid foods occurs, the omega-3 fatty acid intake, particularly of DHA,usually drops dramatically7. This is of concern, considering that several studies have shownthat children withlow dietary DHA intake performed worse in tasks thatmeasure brain development4.
The eye is another important organ that is dependent on omega-3 fatty acids. 30-50% of the retina of the eye (the part that receives light signals) is made from the omega-3 fatty acid DHA. Several studies have shown that infants who were breast-fed or received formula supplemented with DHA and ARA had better clearness of vision than infants that received formula without added DHA and ARA8.
Besides its critical role in visual and brain development, omega-3 fatty acids may also be useful in supporting the child's immune system and heart health9. Omega-3 fatty acids, especially EPA, have anti-inflammatory properties10. Recent studies suggest that the provision of EPA and DHA to infants, toddlers and children reduces the incidence and the duration of illness11-13, and protects them against allergies and eczema14. Unfavorable blood lipids and high blood pressure are now also observed in young children15.It has been suggested that early intake of DHA and ARA may reduce the risk for cardiovascular disease later in life16.
According tothe latest available information on the food intake of South African children, the averageamount of fat consumed is not exceeding the recommended 30–35% of energy for children older than 6 months of age17, 18. However, the quality (type) of fat in the diet of South African children requires attention19.The three most popular food groups that supply fats consumed by South African children 1–5 and 6–9 years are milk, meat and vegetable fats and oils20. Full cream milk is the major food item consumed by both age categories, followed by brick margarine and chicken meat. Also, salty snacks, confectionary products (e.g. cookies, cakes and tart), and non-dairy creamers are among the top ten food items that contribute to fat intake in South African children, most of which contain high amounts of saturated fatty acids and often also contain trans fats. Trans fats have many health risks and are produced during manufacturing when liquid oils are converted to more solid oils (e.g brick margarines, shortenings). Furthermore, South African children are increasingly exposed to fast foods21, which are generally high in total fat and saturated fatty acids.
In order to improve the quality of fat intake in South African children, processed foods (e.g. polony, viennas, pies, etc.) and fast foods should be avoided or eaten infrequently. Soft tub margarines that contain polyunsaturated fatty acids, preferentially high in omega-3 fatty acids, and that are labeled as "trans fat free" should be chosen overhard brick margarines and butter.Vegetable oils rich in polyunsaturated fatty acidsrather than hard fats should be chosen for food preparation. However, not all oilsshould be used for frying and deep frying of foods, because they can produce compounds detrimental to health when heated to high temperatures.Most suitable for frying are canola oil, olive oil (but avoid Extra Virgin) and sunflower oil. Furthermore, frying oils should be replaced after each use. Nevertheless, the amount of fried foods in a child's diet should be limited. In order to increase the intake of EPA and DHA, it is advised that children eat two portions of fatty fish per week. Therefore, it is recommended to introduce fish early in the diet of children to ensure that fish is consumed on a regular basis throughout life.
In summary, fat plays an important role in a child's diet. Fat is not only a source of energy but is crucial for the development of the brain and eye, as well as a healthy heart and immune system. Therefore, not only the amount but also the type of fat in a child's diet is critical19.
1. Huffman SL, Harika RK, Eilander A, Osendarp SJ. Essential fats: how do they affect growth and development of infants and young children in developing countries? A literature review. Matern Child Nutr 2011 Oct;7 Suppl 3: 44-65. 2. Siri-Tarino PW, Sun Q, Hu FB, Krauss RM. Saturated fatty acids and risk of coronary heart disease: modulation by replacement nutrients. Curr Atheroscler Rep 2010 Nov;12(6): 384-90. 3. Brenna JT, Salem N, Jr., Sinclair AJ, Cunnane SC. Alpha-Linolenic acid supplementation and conversion to n-3 long-chain polyunsaturated fatty acids in humans. Prostaglandins Leukot Essent Fatty Acids 2009 Feb-Mar;80(2-3): 85-91. 4. Kuratko CN, Barrett EC, Nelson EB, Salem N. The Relationship of Docosahexaenoic Acid (DHA) with Learning and Behavior in Healthy Children: A Review. Nutrients 2013 Jul;5(7): 2777-810. 5. Lassek WD, Gaulin SJ. Maternal milk DHA content predicts cognitive performance in a sample of 28 nations. Matern Child Nutr 2013 Jun 25. 6. Innis SM. Human milk: maternal dietary lipids and infant development. Proc Nutr Soc 2007 Aug;66(3): 397-404. 7. Michaelsen KF, Hoppe C, Roos N, et al. Choice of foods and ingredients for moderately malnourished children 6 months to 5 years of age. Food Nutr Bull 2009 Sep;30(3 Suppl): S343-404. 8. Hoffman DR, Boettcher JA, Diersen-Schade DA. Toward optimizing vision and cognition in term infants by dietary docosahexaenoic and arachidonic acid supplementation: a review of randomized controlled trials. Prostaglandins Leukot Essent Fatty Acids 2009 Aug-Sep;81(2-3): 151-8. 9. Swanson D, Block R, Mousa SA. Omega-3 fatty acids EPA and DHA: health benefits throughout life. Adv Nutr 2012 Jan;3(1): 1-7. 10. Wall R, Ross RP, Fitzgerald GF, Stanton C. Fatty acids from fish: the anti-inflammatory potential of long-chain omega-3 fatty acids. Nutr Rev 2010 May;68(5): 280-9. 11. Minns LM, Kerling EH, Neely MR, et al. Toddler formula supplemented with docosahexaenoic acid (DHA) improves DHA status and respiratory health in a randomized, double-blind, controlled trial of US children less than 3 years of age. Prostaglandins Leukot Essent Fatty Acids 2010 Apr-Jun;82(4-6): 287-93. 12. Mazurak VC, Lien V, Field CJ, Goruk SD, Pramuk K, Clandinin MT. Long-chain polyunsaturated fat supplementation in children with low docosahexaenoic acid intakes alters immune phenotypes compared with placebo. J Pediatr Gastroenterol Nutr 2008 May;46(5): 570-9. 13. Thienprasert A, Samuhaseneetoo S, Popplestone K, West AL, Miles EA, Calder PC. Fish oil n-3 polyunsaturated fatty acids selectively affect plasma cytokines and decrease illness in Thai schoolchildren: a randomized, double-blind, placebo-controlled intervention trial. The Journal of pediatrics 2009 Mar;154(3): 391-5. 14. Hageman JH, Hooyenga P, Diersen-Schade DA, Scalabrin DM, Wichers HJ, Birch EE. The impact of dietary long-chain polyunsaturated fatty acids on respiratory illness in infants and children. Curr Allergy Asthma Rep 2012 Dec;12(6): 564-73. 15. Kavey RE, Daniels SR, Lauer RM, Atkins DL, Hayman LL, Taubert K. American Heart Association guidelines for primary prevention of atherosclerotic cardiovascular disease beginning in childhood. Circulation 2003 Mar 25;107(11): 1562-6. 16. Forsyth JS, Willatts P, Agostoni C, Bissenden J, Casaer P, Boehm G. Long chain polyunsaturated fatty acid supplementation in infant formula and blood pressure in later childhood: follow up of a randomised controlled trial. BMJ2003 May 3;326(7396): 953. 17. FAO. Fats and fatty acids in human nutrition - Report of an expert consultation. Rome; 2010 10-14 November 2008, Geneva. 18. Labadarios D, Steyn N, Maunder E, et al. The National Food Consumption Survey (NFCS): South Africa, 1999. Public Health Nutr 2005;8(05): 533-43. 19. Smuts CM, Wolmarans PW. The importance of the quality or type of fat in the diet: a food-based dietary guideline for South Africa. South African Journal of Clinical Nutrition 2013;26(3, Suppl.): S87-S99. 20. Nel JH, Steyn NP. Report on South African food consumption studies undertaken amongst different population groups (1983–2000): Average intakes of foods most commonly consumed Pretoria, South Africa; 2002. 21. Feeley A, Norris SA, Pettifor JM. Fast-food consumption among 17-year-olds in the birth to twenty cohort. South African Journal of Clinical Nutrition 2009 01 / 01 /;22(3): 118-23.