ТОП просматриваемых книг сайта:
.
Читать онлайн.
Macronutrients and omega‐3 fatty acids
In 1972, Bang and Dyerberg reported that the low prevalence of coronary heart disease in the Greenland Eskimos was attributable to diet.51 They went on to discover that that the plasma of Greenland Eskimos was higher in eicosapentaenoic acid (EPA) (enriched in marine diet) and lower in arachidonic acid than that of Eskimos living in Denmark52 and that EPA had anti‐atherogenic properties, further explaining the differences in CAD prevalence among the populations. General recommended intake of the essential omega‐3 fatty acid alpha‐linolenic acid (ALA), the substrate for EPA, is 1.1 g for women and 1.6 g for men age 51 and older. Although there is no consensus on the intake of EPA and docosahexaenoic acid (DHA) in the US, Dieticians of Canada (2013) recommend intake of at least two servings of fish per week, thus providing approximately 0.3–0.45 g of EPA and DHA per day. This is an area for future work, particularly in the elderly, where elongation of ALA to these EPA and DHA polyunsaturated fatty acids (PUFAs) are limited (4% at best). Sources of ALA are plant‐based (flax and chia seeds, walnuts, and echium seed oil), and EPA and DHA are exclusively marine sourced (liver of lean white fish such as cod and halibut and the body of oily fish such as mackerel, menhaden, and salmon). These fatty acids are also abundant in the blubber of marine mammals such as seals and whales.53
While DHA is the most abundant omega‐3 in the brain (~10,000 nmol/g of whole brain or 35% of grey matter), its precursor EPA concentrations are marginal in the CNS (<250 nmol/g).54 However, in situ and in vivo models suggest that the brain’s demand for both EPA and DHA are similar, but EPA is rapidly metabolized and esterified to glia where it is concentrated more abundantly than DHA.54–56 EPA and DHA are substrates for the synthesis of pro‐resolving lipid mediators that may offer benefit to the brain, bone, and muscles either directly or through vascular and anti‐inflammatory mechanisms.57,58 Animal studies indicate that omega‐3 inhibits glial activation and tumour necrosis factor (TNF) alpha expression and optimises phospholipase A2 activity.59 These findings have been confirmed in clinical trials where reductions in peripheral TNF‐alpha, increases in some indicators of white matter integrity,60 and cerebral perfusion are seen with omega‐3 supplementation.61 Blood measurement (plasma and erythrocyte membrane concentrations) of the omega‐3 PUFA can provide a reliable indication of n‐3 PUFA status (EPA+DHA). Omega‐3 PUFA (EPA+DHA) >5% of total fatty acids or plasma EPA+DHA >110 ug/ml may offer neuroprotection in older adults62,63
Dietary guidelines and clinical applications
This chapter has summarized nutritional approaches for preventing osteoporosis and fractures, sarcopenia and frailty, and cognitive decline and dementia. Epidemiological studies on nutrition and healthy ageing show that the guidelines for elderly people are very similar to those formulated for younger adults. However, in older adults, it may be imperative to consider dietary supplementation in cases where diet is inadequate and digestion and absorption issues are present (e.g. Celiac disease, Cohn’s disease; high‐quality multivitamin with breakfast). Maintaining a stable body weight and fat‐free mass by sufficient physical activity is important (20–45 minutes per day). The diet should contain higher consumption of green leafy vegetables, nuts and seeds, berries, beans and whole grains, fish, poultry, and olive oil and possibly one glass of wine with a meal. Reductions in red meats, butter and stick margarine, cheese, pastries, sweets, and fried or fast food are recommended.
A clinical laboratory can monitor nutritional status relevant to the promotion of healthy ageing. For instance, 25‐OH‐vitamin D, homocysteine and related B vitamins, and omega‐3 fatty acids are available to the clinician to rule out reversible causes of dementing and mobility illnesses. Frail elders with an inadequate energy intake may need enriched or fortified foods with vitamins, minerals, amino acids, and lipids added according to the healthcare provider recommendations.
In conclusion, many questions remain about how best to individualize nutritional approaches to sustain healthy ageing. However, new initiatives in precision nutrition are materializing to move from population recommendations that work only in subsets of the population to more personalized approaches that maximize individual benefit.64 Companion diagnostics that reliability quantify and monitor nutritional status will play off the success of individualized nutrition in the future.65
Key points
The relative risks of chronic disease is less pronounced with high BMI with old age. If weight loss therapy is indicated in obese elderly, it should result in a minimum loss of lean body mass, especially in older sarcopenic obese people.
A low energy intake (<6.3 MJ/1500 kcal) generally corresponds with an insufficient supply of micronutrients. Therefore, in frail elderly people, the focus with meals should be on tasty, nutrient‐dense foods.
Dietary patterns are available to recommend for specific conditions, as are clinical laboratories to assess nutritional status objectively. These nutritional approaches are most likely to add benefit when tailored to the individual needs based on current nutritional status and diet.
References
1 1. World Population Prospects. United Nations; 2019.
2 2. Baumgartner RN, Stauber PM, McHugh D, Koehler KM, Garry PJ. Cross‐sectional age differences in body composition in persons 60+ years of age. J Gerontol A Biol Sci Med Sci. 1995; 50:M307–16.
3 3. Kirkwood TB. Gerontology: Healthy old age. Nature 2008; 455:739–40.
4 4. Janssen I. Morbidity and mortality risk associated with an overweight BMI in older men and women. Obesity (Silver Spring). 2007; 15:1827–40.
5 5. Deurenberg P, Deurenberg‐Yap M. Ageing and changes in body composition: the importance of valid measurements. In: M Raats, ed. Food for the Ageing Population. Woodhead Publishing; 2009:169–83.
6 6. Cruz‐Jentoft AJ, Baeyens JP, Bauer JM, et al. Sarcopenia: European consensus on definition and diagnosis: Report of the European Working Group on Sarcopenia in Older People. Age Ageing. 2010; 39:412–23.
7 7. de Groot LC, Verheijden MW, de Henauw S, Schroll M, van Staveren WA, Investigators S. Lifestyle, nutritional status, health, and mortality in elderly people across Europe: a review of the longitudinal results of the SENECA study. J Gerontol A Biol Sci Med Sci. 2004; 59:1277–84.
8 8. Marton KI, Sox HC, Jr, Krupp JR. Involuntary weight loss: diagnostic and prognostic significance. Ann Intern Med. 1981; 95:568–74.
9 9. Payette H, Coulombe C, Boutier V, Gray‐Donald K. Nutrition risk factors for institutionalization in a free‐living functionally dependent elderly population. J Clin Epidemiol. 2000; 53:579–87.
10 10. de Groot CP, van den Broek T, van Staveren W. Energy intake and micronutrient intake in elderly Europeans: seeking the minimum requirement in the SENECA study. Age Ageing. 1999; 28:469–74.
11 11. Folsom AR, Kushi LH, Anderson KE, et al. Associations of general and abdominal obesity with multiple health outcomes in older women: the Iowa Women’s Health Study. Arch Intern Med. 2000; 160:2117–28.
12 12. Canoy D. Distribution of body fat and risk of coronary heart disease in men and women. Curr Opin Cardiol. 2008; 23:591–8.
13 13. Schols JM, De Groot CP, van der Cammen TJ, Olde Rikkert MG. Preventing and treating dehydration in the elderly during periods of illness and warm weather. J Nutr. Health Aging. 2009; 13:150–7.
14 14.