Cancer
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Cancer occurs when cells in the body develop a series of mutations which cause them to divide uncontrollably. This can occur in a wide range of tissues resulting in over 200 different types of cancer. Some cancers can spread to other areas of the body in a process termed metastasis.
1 in 2 people in the UK born after 1960 will be diagnosed with some form of cancer during their lifetime, with the most common four types (breast, lung, prostate and bowel) accounting for over half of all new cases in the UK1.
Prevention and Management
A wide range of lifestyle factors have been implicated in contributing to cancer risk, the most important of these being tobacco smoking. Other factors include diet, body weight, alcohol consumption, physical activity, certain infections and exposure to UV light. A recent review of the evidence estimated that in the UK, 43% of cancer cases are preventable and around 9% of cancers could be attributed to an unhealthy diet2. Whilst it is difficult to determine which dietary constituents may help prevent or contribute to cancer risk due to the nature of research in this area, the review concluded that:
· A low consumption of fruit and vegetables may increase cancer risks at a number of sites including the oral cavity, pharynx, oesophagus and larynx.
· Consumption of red and processed meats may increase risk of colorectal cancer
· A low fibre diet may increase risk of colorectal cancer
· High salt intakes may increase risk of stomach cancer
As excess body weight was found to be the third most common lifestyle risk factor for cancer after tobacco and diet, promoting a healthy lifestyle with a varied, balanced diet and regular physical activity should play a central role in cancer prevention.
Sugar and cancers
Experts working with World Cancer Research Fund International3 have reviewed the scientific evidence on sugar intake and cancer. This report suggested a possible increased risk of colorectal cancer where intakes of sugar-rich foods are high, however the evidence was described as sparse and inconsistent3,4. In 2015, the Scientific Advisory Committee on Nutrition’s Carbohydrates and Health Report concluded that there was a lack of evidence to enable conclusions to be drawn on sugars intake and colorectal cancer, but found no association between colorectal cancer incidence and sugar-sweetened beverage intake5.
References
1 Cancer research UK (2015) http://www.cancerresearchuk.org/health-professional/cancer-statistics (accessed 30/11/15)
2 Parkin, D. M. (2011). The fraction of cancer attributable to lifestyle and environmental factors in the UK in 2010. British Journal of Cancer. 105, Supp. 2
3 World Cancer Research Fund/American Institute for Cancer Research, Food, nutrition, physical activity and the prevention of cancer: a global perspective. 2007, Washington DC: AICR.
4 World Cancer Research Fund / American Institute for Cancer Research. Continuous Update Project Report. Food, Nutrition, Physical Activity, and the Prevention of Colorectal Cancer. 2011
5 SACN (2015) Carbohydrates and Health Report
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/445503/SACN_Carbohydrates_and_Health.pdf (accessed 20/07/15)
Cardiovascular Disease
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Cardiovascular disease (CVD) accounts for around a quarter of all UK deaths annually, and is a major cause of illness and disability with a further 7 million people in the UK estimated to be living with the diease1. The term CVD describes all conditions which affect the heart and circulatory system, including diseases of blood vessels supplying the heart (coronary heart disease), the brain (cerebrovascular disease) and the arms and legs (peripheral arterial disease).
Causes
Deaths from CVD often occur as a result of acute events such as heart attack or stroke, and are preceded by the development of fatty deposits inside the arterial wall termed atherosclerotic plaques. These cause a narrowing of the blood vessel, reducing the blood flow to the area they supply. Whilst a stable plaque may cause chest pains (angina), unstable plaques are more liable to rupture exposing the contents of the fatty deposit to the circulating blood. This can activate platelet aggregation and development of a thrombus, which can occlude major blood vessels causing heart attack and stroke.
Prevention & Management
A range of risk factors have been described for CVD, such as tobacco use, unhealthy diet and obesity, physical inactivity and excessive use of alcohol, hypertension, diabetes and abnormal blood lipids (hyperlipidaemia). Family history of heart disease and ethnicity may also increase risk.
Despite most acute events occurring in the middle-aged and elderly, the progression of atherosclerosis develops throughout life, and in the early stages is largely reversible. Lifestyle modification is therefore the focus of preventative strategies and includes maintaining a healthy weight, stopping smoking, remaining physically active and eating a balanced diet low in saturated fat. Guidance suggests that where possible, saturated fat is replaced by mono-unsaturated or polyunsaturated fats by using olive or rapeseed oil or spreads based on these oils in food preparation2.
Activity recommendations for adults advise at least 150 minutes of moderate intensity activity such as brisk walking or cycling, or 75 minutes of vigorous activity such as running every week. In addition, strength exercises that work all the major muscles should be performed at least two days a week.
Sugar and cardiovascular disease
In 2015, the Scientific Advisory Committee on Nutrition’s Carbohydrates and Health Report3 found no association between incidence of coronary events and sugars intake. It was reported that there was insufficient evidence to draw conclusions on the impact of sugars intake on cardiometabolic risk factors.
References
1 British Heart Foundation (2015) – https://www.bhf.org.uk/research/heart-statistics (accessed 12/11/15)
2 NICE guideline: Cardiovascular disease: risk assessment and reduction, including lipid modification (2014) http://www.nice.org.uk/guidance/cg181/chapter/1-recommendations (accessed 12/11/15)
3 SACN (2015) Carbohydrates and Health Report
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/445503/SACN_Carbohydrates_and_Health.pdf (accessed 20/07/15)
Dental health
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One of the greatest health achievements in the last 40 years has been the improvement in dental health, particularly in children. Tooth decay has become much less common due to the introduction of fluoride toothpaste during the 1970s1. Data from the Children’s Dental Health Survey indicates a general decline in tooth decay. In fact, the number of decayed, missing or filled teeth (DMFT) in 12 year olds has fallen from 4.7 in 1973 to 0.8 in 20132,3. However despite these improvements, tooth decay and poor oral health continue to pose a major health problem worldwide.
Causes
Eating or drinking fermentable carbohydrates – both sugary sources such as sugar, fruit and juices, and starchy sources such as bread, rice, and pasta – causes some damage to the teeth if consumed too frequently. Fruit contains a number of sugars (sucrose, fructose and glucose) while starches are readily broken down by enzymes in saliva to glucose and maltose. Bacteria in the mouth, including Mutans streptococci and Lactobacilli, can convert the sugars in food and drinks to acid that attacks the enamel surface of the teeth, causing demineralisation. Hence, a wide variety of carbohydrate-containing foods will contribute to the decay process if they are consumed too frequently, and where poor oral hygiene is observed.
Tooth decay is only one of the dental health concerns. Erosion of the tooth surface is increasingly being recognized as a growing problem. It can be caused by eating acidic foods, such as pickles, or sipping acidic drinks, like orange juice, too frequently.
Prevention and management
Tooth decay can occur under a range of conditions. The latest recommendations to prevent dental caries suggest a reduction in the frequency and amount of sugary food and drinks, with sugars to be consumed on no more than four occasions per day. Alongside this, twice daily brushing of the teeth with fluoride toothpaste is the best way to prevent caries4. Sugary and acidic drinks should ideally be reduced but if consumed should be enjoyed at mealtimes.
Thorough and regular tooth care will help prevent the decay-promoting bacteria from becoming established. Brushing last thing at night is particularly important, as the protective effect of saliva is reduced during sleep. Reducing eating frequency allows tooth enamel to repair, using the calcium and phosphate present in saliva, provided some time elapses between acid attacks. Chewing stimulates the production of saliva and helps this repair process.
Sugars and dental health
The Scientific Advisory Committee on Nutrition’s (2015)5 Carbohydrates and Health Report found an association between the amount of sugars, sugars-containing foods and beverages intake and dental caries. A higher frequency of consumption of sugar-containing foods and beverages, but not sugars, was also associated with greater risk of dental caries. Therefore it is not only amount but also frequency of consumption that is the issue for dental caries risk. Regularly eating fermentable carbohydrates including sugars, i.e., foods that react with bacteria in the mouth to create acids, is a risk factor for tooth decay because eating more regularly allows less time for saliva to balance the damage to teeth from acids. Therefore considering how often you eat, as well as what you eat, is key.
Carbohydrates, mainly from starchy sources, should make up the bulk of a healthy balanced diet but it is important to maintain good oral health practices including brushing twice a day with fluoride toothpaste.
Click here to access our free dental resources.
References
1 Cottrell, R. C. (2011) Dental disease: Etiology and epidemiology. IN CABALLERO, B., ALLEN, N. & PRENTICE, A. M. (Eds.) Encyclopaedia of Human Nutrition. 2nd Edition ed. Kidlington, UK, Elsevier Academic Press.
2 WHO Oral health database, Malmö University. Available from http://www.mah.se/CAPP/Country-Oral-Health-Profiles/EURO/European-Union-and-European-Economic-Area–/Dental-Caries-for-12-year-olds/ (accessed 13/07/15)
3 Children’s Dental Health Survey (2013) http://www.hscic.gov.uk/catalogue/PUB17137/CDHS2013-Executive-Summary.pdf (accessed 22/09/15)
4 PHE (2014)
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/367563/DBOHv32014OCTMainDocument_3.pdf (accessed 14/07/15)
5 SACN (2015) Carbohydrates and Health Report
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/445503/SACN_Carbohydrates_and_Health.pdf (accessed 20/07/15)
Diabetes
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Diabetes mellitus is a common metabolic disorder which affects around 3.3 million people in the UK, with a further 590,000 thought to be undiagnosed1. More than three-quarters of people with diabetes have type 2 diabetes (T2DM).
There are two main types of diabetes mellitus, type 1 and type 2. Type 1 develops when the cells in the pancreas that produce insulin are destroyed by the body’s immune system. Insulin is the hormone which controls blood glucose, and is produced by the pancreas in response to ingestion of dietary carbohydrates and protein. Type 1 usually occurs in people under the age of 40, commonly during childhood, and is treated by regular insulin injections and careful dietary control and modification.
In type 2, the pancreas does produce some insulin but either in an inadequate amount or its utilisation is less effective. It generally occurs in people over the age of 40 – occasionally in younger people – and is caused by a combination of factors, one being overweight. T2DM can often be treated by dietary modifications alone, or by a combination of diet and pharmacotherapy, including glucose-lowering medication or insulin injections. The majority of people with T2DM are overweight, therefore weight management is a crucial aspect of prevention and management. Diabetes prevention programmes can reduce T2DM progression and improve related symptoms including weight and glucose levels2.
Prevention and management
The aim of nutritional management of diabetes is to optimise blood glucose control and reduce the risk of diabetic complications. The diet for people with diabetes follows the basic principles of healthy eating including reducing saturated fat intake3. Despite diabetes being a condition of blood glucose regulation, specific restriction of sugars is not necessary except to ensure a balanced diet, although incorporating a low glycaemic index diet may be beneficial in reducing T2DM risk factors4.
Management of T2DM in those who are overweight or obese is particularly focussed on achieving and maintaining a healthy body weight through diet and physical activity. Recommendations support a diet low in saturated fats, particularly in high risk groups5. Overweight individuals with diabetes should be encouraged to reduce their energy intake and increase their physical activity levels, as even modest weight loss will improve blood glucose control and other metabolic abnormalities associated with the disease. Research indicates that it may be possible to reverse T2DM through reduced dietary energy intake alone6, and evidence shows that following a diabetes prevention programme can reduce the risk of developing T2DM by 26%2.
Weight loss can also improve insulin resistance, which occurs when cells do not respond effectively to insulin and glucose is therefore not absorbed properly. This can lead to prediabetes or T2DM if lifestyle changes are not adopted.
Sugars and Diabetes
The concept that consumption of sugars may cause diabetes has been the focus of much research over the years. The UK Government’s COMA Committee (1989)7 discounted this link in 1989. More recently the Scientific Advisory Committee on Nutrition’s Carbohydrates and Health Report (2015) found no association between T2DM incidence and total or individual sugars intake. However it did highlight an association between greater consumption of sugars-sweetened beverages and risk of T2DM8.
References
1 Diabetes UK (2015) https://www.diabetes.org.uk/Guide-to-diabetes/What-is-diabetes/ (accessed 17/06/15)
2 PHE (2015) A Systematic review and meta-analysis assessing the effectiveness of pragmatic lifestyle interventions for the prevention of type 2 diabetes mellitus in routine practice
3 Diabetes UK (2011) Evidence-based nutrition guidelines for the prevention and management of diabetes
https://www.diabetes.org.uk/Documents/Reports/nutritional-guidelines-2013-amendment-0413.pdf (accessed 22/09/15)
4 Bhupathiraju, Shilpa N; Tobias, Deirdre K; Malik, Vasanti S; Pan, An; Hruby, Adela; Manson, JoAnn E; Willett, Walter C and Hu, Frank B (2014) Glycemic index, glycemic load, and risk of type 2 diabetes: results from 3 large US cohorts and an updated meta-analysis. Am J Clin Nutr doi:10.3945/ajcn.113.079533
5 Dyson, P.A., Kelly, T., Deakin, T., Duncan, A., Frost, G., Harrison, Z., Khatri, D., Kunka, D., McArdle, P., Mellor, D., Oliver, L. & Worth, J. (2011) Diabetes UK evidence-based nutrition guidelines for the prevention and management of diabetes. Diabet Med, vol.28, pp. 1282-1288
6 Lim, EL; Hollingsworth, KG; Aribisala, BS; Chen, MJ; Mathers, JC; Taylor, R (2011) Reversal of type 2 diabetes: normalisation of beta cell function in association with decreased pancreas and liver triacylglycerol. Diabetologia 54(10):2506-14. doi: 10.1007/s00125-011-2204-7
7 COMA (1989) Dietary Sugars and Human Disease. Report on Health and Social Subjects. No 37, HMSO, Department of Health, London
8 SACN (2015) Carbohydrates and Health Report
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/445503/SACN_Carbohydrates_and_Health.pdf (accessed 20/07/15)
Non-alcoholic fatty liver disease
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Non-alcoholic fatty liver disease (NAFLD) is a term used to describe excess fat in the liver (steatosis) in the absence of excessive alcohol consumption or any of the other secondary causes of steatosis.
There are four main stages of NAFLD progression:
1) Simple steatosis
2) Non-alcoholic steatohepatitis (NASH)
3) NASH with fibrosis
4) Cirrhosis
NAFLD is one of the most common liver diseases worldwide with an estimated prevalence of 25-30% of the UK population1. The majority of cases are simple steatosis which carries a low risk of progression to more serious forms of the disease, and is largely asymptomatic. Approximately 2 to 5% of the UK population have NASH which is characterised by inflammation of the liver and has more serious implications for the development of scarring (fibrosis) and permanent damage (cirrhosis) which can lead to liver failure or cancer.
Causes
Most but not all individuals with NAFLD are overweight or obese, and there is a strong association with type II diabetes. Individuals with high blood pressure and dyslipidaemia (abnormal blood lipids) are also at increased risk.
Prevention and Management
Losing excess weight through lifestyle intervention is the main focus for preventing and reducing the accumulation of fat in the liver. A systematic review2 of 23 studies of diet, exercise or diet combined with exercise interventions consistently showed that weight reduction and/or increased physical activity led to a decrease in liver fat as well as improvements in glucose control and insulin sensitivity. Weight losses of 4-14% resulted in considerable relative reductions in liver fat ranging from 35 to 81%. The degree of weight loss achieved was shown to be important with strong correlations found between amount of weight lost and reduction in liver fat.
Whilst diagnosis of NALFD is restricted to those who do not consume excessive alcohol, it is likely that for many individuals both obesity and alcohol contribute to liver fat and risk of progressive liver disease, therefore a reduction in alcohol intake is recommended3. Following a healthy, balanced diet, not smoking and carefully managing existing conditions such as diabetes, may also help to prevent progression of the disease.
National Institute of Health Care and Excellence expect to publish guidance on this condition in July 2016
https://www.nice.org.uk/guidance/indevelopment/gid-cgwave0692/documents
Sugar and NAFLD
Excess energy intake is associated with the risk of developing NAFLD. The role of diet composition is unclear and requires further research2. Available evidence is insufficient to implicate sugars such as fructose or sucrose alone in NAFLD4.
References
1 NHS (2015) http://www.nhs.uk/conditions/fatty-liver-disease/Pages/Introduction.aspx (accessed 28/10/15)
2 Thoma, C et al. (2012) Lifestyle interventions for the treatment of non-alcoholic fatty liver disease in adults: A systematic review. Journal of Hepatology , 56 (1) , pp.255 – 266
3 Sattar, N et al (2014) Non-alcoholic fatty liver disease. BMJ (349):g4596
4 Chung et al (2014) Fructose, high-fructose corn syrup, sucrose, and non-alcoholic fatty liver disease or indexes of liver health: a systematic review and meta-analysis. Am J Clin Nutr doi: 10.3945/ajcn.114.086314
Obesity
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Obesity is a considerable health problem in the UK. Currently, over half of the adult population is overweight, with 26% of men and 23.8% of women now classified as obese1. Excess weight is a major risk factor for premature death, cardiovascular disease, type 2 diabetes, certain cancers and other chronic health problems.
Definition
Obesity refers to an accumulation of excess body fat. Although it would be more effective to assess body composition, the simpler calculation of body mass index (BMI) is more commonly used. BMI is a marker for obesity and is calculated by dividing an individual’s weight (in kilograms) by the square of their height (in metres). BMI does not, however, account for the distribution of body fat, which may differ between race, gender and age. For instance, excess fat stored around the abdomen – central obesity (apple shaped) – is more commonly associated with health risks, such as diabetes and cardiovascular disease, than fat stored elsewhere.
Causes
A great deal of scientific study has been undertaken in an attempt to understand why some people become overweight and obese. Researchers have also tried to devise the best methods for losing weight and to assess the effects of weight loss on health.
Maintenance of energy balance is dependent both on energy intake and energy expenditure. If energy intake from food and drink exceeds the amount used for physical activity and metabolic functions, the excess is stored as body fat, resulting in weight gain. The optimal combination to avoid positive energy balance and obesity is a healthy, balanced diet and regular physical activity.
There is increasing acknowledgement that the emerging epidemic of obesity cannot simply be attributed to dietary factors2. One of the clearest indications to support this is the fact that, in general, energy intakes are declining while average body weight is increasing. For example, mean daily total energy intake for men decreased from 2313kcal in 2003 to 2111 kcal in 2012. For women it decreased from 1632kcal in 2003 to 1613 kcal in 20123,4. Alongside this, the proportion of adults globally with a BMI of ≥25 kg/m² increased from 28.8% to 36.9% in men and from 29.8% to 38% in women between 1980 and 20135.
Prevention and management
The available evidence recommends a balanced diet limiting high fat foods for general health. Research has shown that reducing the proportion of fat in the diet leads to weight loss, even when energy intake is not consciously restricted6. More recently, Hall et al (2015)7 noted that, calorie for calorie, restricting dietary fat led to greater body fat loss than restricting dietary carbohydrate in obese adults, although it should be noted that the study method used a highly restrictive in-patient environment rather than a free living environment.
It is important to note that overall energy balance is the key factor and overconsumption of dietary energy from any macronutrient source is likely to lead to weight gain. Any diet which restricts calories is likely to work in the short term however the goal should be to maintain a lifestyle change which will ensure longer term weight loss success. Weight loss that is too rapid may cause serious health problems, so it is generally recommended that those looking to lose weight should aim to lose no more than 1kg (2lb) per week. A reasonable target is to try to lose 1kg every 2 weeks. In addition, dietary advice should ideally be tailored according to individual’s specific needs.
Physical activity
Physical activity is recommended to reduce the risk of physical, metabolic, hormonal and psychological complications, and improve an individual’s mental wellbeing by reducing anxiety and depression8. Indeed, studies have suggested that improving overall fitness should be emphasised more heavily than simply reducing weight, and there is a growing body of evidence that suggests high physical fitness is a better predictor of more favourable cardiovascular disease prognosis than measures of weight9. It has been argued that under certain limited circumstances obese individuals may have healthier cardiorespiratory and metabolic fitness levels than those within a healthy weight range. This potential protective effect of obesity is known as the ‘obesity paradox’10.
Physical activity is associated with improved motivation and therefore with better dietary compliance, increased lean body mass, and an amelioration of the usual suppression of metabolic rate which accompanies weight loss. Participation in some form of exercise seems to be a key element of successful weight loss and longer-term maintenance success11.
Sugars and obesity
According to the Scientific Advisory Committee on Nutrition’s Carbohydrates and Health Report, evidence is inadequate to infer a causal relationship between sugars and weight gain or body mass12 when energy intake remains constant. An effect was however noted in children and adolescents between consumption of sugars-sweetened beverages and increased weight gain and body mass index12. In England, adult obesity rates have increased from 13.2% to 24.4% in men and from 16.4% to 25.1% in women between 1993 and 201212. At the same time, intakes of sugars have decreased by approximately 7%4.