Posted by ProPortion Foods Blog on Jul 3, 2017 in Muscle
Type 2 diabetes is a metabolic condition that occurs progressively, beginning with decreased insulin sensitivity in cells, known as insulin resistance, leading to pre-diabetes. Without intervention pre-diabetes will eventually progress to overt type 2 diabetes. One of the most distinctive traits of type 2 diabetes is that it can be managed by diet and lifestyle modifications. In some cases, individuals are able to completely reverse the symptoms.
In type 2 diabetes sufficient insulin is produced initially; the problem lies with the action of insulin on target cells. Instead of producing the usual effects of insulin – that is the uptake of glucose from the blood into cells to provide energy – the effects of insulin are blunted and glucose remains in the blood. In turn, the pancreas produces more insulin in an attempt to maintain normal blood glucose levels, and eventually it cannot keep up with this demand. The end result is not only hyperglycaemia but also high blood insulin levels. This state is referred to as pre-diabetes. At this stage blood glucose levels are slightly elevated, yet not to the levels seen in overt diabetes.
In an attempt to normalise these high blood glucose levels, the pancreas over compensates and secretes more insulin. This state can last for years until continued over production of insulin eventually degrades and damages pancreatic beta cells resulting in overt type 2 diabetes. At this point there is both a decrease in the effectiveness of insulin and reduced insulin production (1).
The majority – around 80% – of glucose uptake after a meal occurs in muscle tissue, making muscle an important site of glucose disposal. Increasing muscle mass can decrease progression of insulin resistance regardless of overall body size.
It has been demonstrated in observational studies that increased muscle mass may reduce the risk of type 2 diabetes. A cross sectional analysis of the National Health and Nutrition Examination Survey III using data from 13,644 participants concluded that higher percentages of muscle mass were associated with increased insulin sensitivity; researchers also noted an inverse relationship between muscle mass and risk of pre-diabetes (2).
This is significant for both prevention and management interventions. Regular resistance exercise and preservation of muscle mass, especially as we age, could in fact lower the risk of developing diabetes and other metabolic diseases (3, 4). Unfortunately, this can be rather challenging for those with type 2 diabetes as they are prone to muscle atrophy, likely resulting from decreased activity of anabolic hormones. This is especially prevalent in elderly diabetics (5). For this reason, it is important to consider dietary management to accompany increased and regular exercise.
Inactivity contributes significantly to the development of type 2 diabetes. Physical activity and regular exercise can enhance blood glucose control and reduce diabetes risk.
Even 30 minutes of moderate exercise per day, such as brisk walking, 5 days a week can reduce diabetes risk by 30% (7). However higher intensity exercise such as running, cycling, swimming for longer durations and the addition of resistance exercise is likely to achieve better results (3, 4).
Sarcopenia (defined as reduced muscle mass through ageing), and sarcopenic obesity (which is the presence of sarcopenia concurrently with obesity), are known risk factors for insulin resistance and type 2 diabetes respectively (5, 10, 11). Preservation of muscle mass is of particular importance in the elderly, especially when either sarcopenia or sarcopenic obesity are present. A structured exercise and dietary intervention can significantly decrease the risk of developing type 2 diabetes in these populations.
Any intervention program for pre-diabetes and type 2 diabetes should focus on both physical activity and diet. A diet containing insufficient protein is likely to have a deleterious effect on muscle mass. This is especially relevant in the elderly, who typically do not consume sufficient protein to help support muscle growth (12). A protein rich diet, when coupled with resistance exercise, has also been shown to improve body composition in type 2 diabetics (13, 14).
1. Rydén L, Standl E, Bartnik M, Van den Berghe G, Betteridge J, De Boer M-J, et al. (2007) Guidelines on diabetes, pre-diabetes, and cardiovascular diseases: executive summary. European heart journal; 28, 88-136.
2. Srikanthan P, Karlamangla AS (2011) Relative muscle mass is inversely associated with insulin resistance and prediabetes. Findings from the third National Health and Nutrition Examination Survey. The Journal of Clinical Endocrinology & Metabolism; 96, 2898-903.
3. Colberg SR, Albright AL, Blissmer BJ, Braun B, Chasan-Taber L, Fernhall B, et al. (2010) Exercise and type 2 diabetes: American College of Sports Medicine and the American Diabetes Association: joint position statement. Exercise and type 2 diabetes. Medicine and science in sports and exercise; 42, 2282-303.
4. Wolfe RR (2006) The underappreciated role of muscle in health and disease. The American journal of clinical nutrition; 84, 475-82.
5. Park SW, Goodpaster BH, Lee JS, Kuller LH, Boudreau R, De Rekeneire N, et al. (2009) Excessive loss of skeletal muscle mass in older adults with type 2 diabetes. Diabetes care; 32, 1993-7.
6. Poehlman ET, Dvorak RV, DeNino WF, Brochu M, Ades PA (2000) Effects of Resistance Training and Endurance Training on Insulin Sensitivity in Nonobese, Young Women: A Controlled Randomized Trial 1. The Journal of Clinical Endocrinology & Metabolism; 85, 2463-8.
7. Hu FB, Sigal RJ, Rich-Edwards JW, Colditz GA, Solomon CG, Willett WC, et al. (1999) Walking compared with vigorous physical activity and risk of type 2 diabetes in women: a prospective study. Jama; 282, 1433-9.
8. Group DPPR (2015) Long-term effects of lifestyle intervention or metformin on diabetes development and microvascular complications over 15-year follow-up: the Diabetes Prevention Program Outcomes Study. The Lancet Diabetes & Endocrinology; 3, 866-75.
9. Eves ND, Plotnikoff RC (2006) Resistance training and type 2 diabetes. Diabetes care; 29, 1933-41.
10. Cleasby ME, Jamieson PM, Atherton PJ (2016) Insulin resistance and sarcopenia: mechanistic links between common co-morbidities. Journal of Endocrinology; 229, R67-R81.
11. Moon S-S (2014) Low skeletal muscle mass is associated with insulin resistance, diabetes, and metabolic syndrome in the Korean population: the Korea National Health and Nutrition Examination Survey (KNHANES) 2009-2010. Endocrine journal; 61, 61-70.
12. Campbell WW, Leidy HJ (2007) Dietary protein and resistance training effects on muscle and body composition in older persons. Journal of the American College of Nutrition; 26, 696S-703S.
13. Wycherley TP, Noakes M, Clifton PM, Cleanthous X, Keogh JB, Brinkworth GD (2010) A high-protein diet with resistance exercise training improves weight loss and body composition in overweight and obese patients with type 2 diabetes. Diabetes care; 33, 969-76.
14. Wycherley TP, Noakes M, Clifton P, Cleanthous X, Keogh J, Brinkworth G (2010) Timing of protein ingestion relative to resistance exercise training does not influence body composition, energy expenditure, glycaemic control or cardiometabolic risk factors in a hypocaloric, high protein diet in patients with type 2 diabetes. Diabetes, Obesity and Metabolism; 12, 1097-105.
15. Wycherley TP, Moran LJ, Clifton PM, Noakes M, Brinkworth GD (2012) Effects of energy-restricted high-protein, low-fat compared with standard-protein, low-fat diets: a meta-analysis of randomized controlled trials. The American journal of clinical nutrition, ajcn. 044321.
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Posted by ProPortion Foods Blog on in Sarcopenia
Sarcopenia can be described as a loss of skeletal muscle mass, muscle function and strength that occurs with aging. Sarcopenia can significantly impact on quality of life and lead to other chronic disease states. Lack of a clinical definition of sarcopenia means that its prevalence in Australia is difficult to determine. However, it is estimated that up to 29% of the community-dwelling population and up to 33% of those in long term care are affected (1). Whilst sarcopenia is often associated with the elderly in aged care, those requiring assistance and frailty, the reality is that muscle decline and sarcopenia begin much earlier in life and often goes unnoticed.
Age is the major determining risk factor for sarcopenia; muscle mass can begin to decline by the 4th decade of life and by the 8th decade total muscle may have declined by up to a 50%. Genetics, lifestyle and the presence of other chronic disease are also contributing factors to loss of muscle mass (2, 3).
As we age the number of muscle fibres, most notably the type 2 fast twitch muscle fibres, begin to decline. Additionally, the precursor or satellite cells – which are activated to repair and build muscle after weight bearing exercise or trauma – also begin to reduce in concentration. These physiological changes make the muscle building and repair process less effective and together with a decline in physical activity and nutritional status contributes to the progression of sarcopenia (2).
When overweight or obesity is present sarcopenia may not be as noticeable, yet it is equally as detrimental to health. This is referred to as sarcopenic obesity, the presence of obesity and sarcopenia together (4). This paradox is often characterised by fat infiltration of muscle; the increase in adipose tissue and decrease in muscle mass drastically alters metabolic processes and is closely associated with insulin resistance and diabetes (5).
As muscle mass makes up 60% of overall body tissue the structural and metabolic consequences of muscle loss are significant (2). This dramatic change in body composition can impact on mobility and lead to frailty, increased risk of falls and fractures, insulin resistance, fatigue and mortality. Sarcopenia can, of course, occur concurrently with other diseases such as rheumatoid arthritis or osteoporosis; when this is the case there is an even greater increase in the risk of fracture, illness and decreased quality of life.
Fortunately, with diet and lifestyle interventions the progression and severity of sarcopenia can be reduced.
Nutrition and diet are the gold standard for the management or prevention of sarcopenia. Older adults generally have a greater relative protein requirement than younger adults. This is due to changes over time in ability to digest protein and, in the case of muscle, decreased sensitivity in older adults of muscle protein synthesis (‘MPS’) pathways. Whilst the current RDI is 0.8g/kg of body weight, recommended intake for older adults often ranges from 1.0 to 1.2g/kg of body weight. This may increase further in the case of chronic disease. The essential amino acid leucine is strongly associated with MPS and consumption of protein sources rich in this amino acid may help improve muscle strength and function (1 2, 6).
The aim should be to include 25-30g of protein with each main meal. Timing these meals post exercise may help increase muscle mass. Exercise programs focussing on resistance exercises, or a blend of both aerobic and resistance or compound exercises, can improve muscle strength and function as well as potentially increasing muscle mass in sarcopenic individuals (1).
Maintenance of overall physical activity, inclusion of resistance exercise and a diet containing sufficient energy and protein can be helpful in the prevention of sarcopenia and should be the cornerstone of a healthy lifestyle as we age (2, 6).
1. Cruz-Jentoft AJ, Landi F, Schneider SM, Zúñiga C, Arai H, Boirie Y, et al. (2014) Prevalence of and interventions for sarcopenia in ageing adults: a systematic review. Report of the International Sarcopenia Initiative (EWGSOP and IWGS). Age and ageing; 43, 748-59.
2. Walston JD (2012) Sarcopenia in older adults. Current opinion in rheumatology; 24, 623.
3. Scott D, Blizzard L, Fell J, Jones G (2011) The epidemiology of sarcopenia in community living older adults: what role does lifestyle play? Journal of cachexia, sarcopenia and muscle; 2, 125-34.
4. Cleasby ME, Jamieson PM, Atherton PJ (2016) Insulin resistance and sarcopenia: mechanistic links between common co-morbidities. Journal of Endocrinology; 229, R67-R81.
5. Stenholm S, Harris TB, Rantanen T, Visser M, Kritchevsky SB, Ferrucci L (2008) Sarcopenic obesity-definition, etiology and consequences. Current opinion in clinical nutrition and metabolic care; 11, 693.
6. Steffl M, Bohannon RW, Sontakova L, Tufano JJ, Shiells K, Holmerova I (2017) Relationship between sarcopenia and physical activity in older people: a systematic review and meta-analysis. Clinical interventions in aging; 12, 835.
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