News
Increased levels of the protective macular pigment in the fovea of the eye are shown to be positively associated with increased blood serum of lutein, zeaxanthin and DHA in a new human study (1)
19 December 2016
01 January 2012
“The National Diet and Nutrition Survey (NDNS) offers the best quality and most representative micronutrient intake data for the UK. While the reference nutrient intake (RNI) is designed to meet the needs of 97.5% of the normal, healthy population, the lower reference nutrient intake (LRNI) only meets the needs of the remaining 2.5%. Therefore, those with intakes below the LRNI are deemed to be at risk of deficiency according to the Dietary Reference Values (1), although actual deficiency can only be determined using biochemical markers. In the NDNS, inadequate intakes were seen for vitamin A, vitamin D, folic acid, iron, calcium, magnesium, zinc and iodine (2), as well as long-chain omega-3 fatty acids (3). Markers of nutritional status gave a different picture showing low blood levels of vitamins C and D, iron and folate (4).
These data suggest that a significant proportion of older people are failing to consume adequate amounts of vitamins, minerals and omega-3 fatty acids. Those most at risk of deficiency include people in their 80s and people in institutions. It is thus called for that older people take multi-nutrient supplements (5), as they appear to be a useful way to boost micronutrient intakes in this age group (6).
Poor diet is known to contribute to the development of type 2 diabetes, heart disease, stroke, osteoporosis and certain cancers (7). While public health messages often focus on reducing intakes of fat, saturated fat, sugar and salt, equal concern is deserved for inadequate intakes of vitamins, minerals and omega-3 fatty acids. Insufficient calcium and vitamin-D intakes throughout adulthood accelerate bone loss in later life, greatly increasing the risk of osteoporosis, fracture and falls (8). A growing number of studies report significant associations between a poor vitamin D status in later life and a greater risk of type 2 diabetes, cardiovascular disease (CVD) and cancer (9), and with faster aging in the DNA of cells, estimated by telomere length (10). Mortality rates from all causes are significantly higher in older people with a poor vitamin D status (11). Studies reveal that cognitive function in later life declines faster and the risk of dementia increase, when intakes of long-chain omega-3 fatty acids are low (12). A longitudinal survey of 1,091 UK adults found better cognitive performance in 70-year-olds who had higher intakes of vitamins B12, C, riboflavin and folate. However, the significance of this association was attenuated when childhood IQ was accounted for (13). Longitudinal studies have associated low B-vitamin status with faster cognitive decline (14), while low intakes of B vitamins have been linked with a higher risk of depression (15). Higher blood levels of antioxidant nutrients, e.g. carotenoids, vitamins C and E, may reduce the risk of CVD, diabetic complications and cancer (16). Two longitudinal surveys in older populations (17, 18) found a lower risk of
all-cause and cancer mortality when blood carotenoid levels were high. A meta-analysis of 15 cohort studies found a 16-24% lower risk of CVD when intakes of vitamins C and E and beta-carotene were high (19). These studies show the disadvantage of micronutrient insufficiency. Researchers suggest that supplements containing vitamins C and E, carotenoids, zinc and selenium could help prevent accelerated aging and reduce the risk of age-related diseases (20).
The research includes a number of long-term supplementation studies in elderly populations. Two of these found improvements in antioxidant capacity following supplementation of zinc, or a combination of zinc, selenium, vitamin C, beta-carotene and vitamin E (21, 22). This may have implications for disease risk as a low antioxidant status has been associated with a greater risk of cancer and CVD (17, 18). Other studies have reported improvements in nutritional status and a reduced risk of micronutrient deficiency with various combinations of vitamin and mineral supplements (23, 24). Other studies considered cognitive function. One long-term study demonstrated improved verbal fluency in older or ‘at risk’ participants following supplemen-tation with 11 vitamins and five minerals (25). Several trials have looked at heart health, revealing benefits for blood pressure, blood lipids, serum homocysteine, anti-inflammatory markers and heart function after the intake of fish oil or multi-nutrient supplements (26-29). These studies suggest improvements in nutritional status and disease markers when older populations take multi-nutrient supplements over the medium to long term. The findings are supported by systematic reviews and meta-analyses of the relationship between bone health and vitamin D supplementation (30, 31), CVD and folic acid supplementation (32), as well as age-related macular degeneration and supplementation with beta-carotene, vitamins C, E and zinc (33). For other conditions, such as atherosclerosis and cancer, the benefits of supplementation are inconsistent.
A varied diet including plenty of fruit, vegetables, whole grains, fish, lean meat and poultry, low-fat dairy foods and starchy carbohydrates should be the bedrock of dietary intervention. However, successive dietary surveys in the UK suggest that the rate of progress towards dietary targets is slow. Poor cooking skills, poor dentition, disabilities and loss of appetite or the sense of taste in older people may also hamper efforts to eat more healthily. As energy-intake requirements decline in old age, in part due to a loss of muscle mass, the diets of older people must remain nutrient-dense in order to meet the recommended requirements. Dietary supplements have an important role in helping older people maintain optimal nutrient intakes, thus reducing the risk of deficiency. Evidence on supplementation in this age group suggests consistent benefits to nutritional status and, in the case of some studies, markers of disease risk. Multi-nutrient supplements, such as multivitamin and multi-mineral formulations, are typically used in these studies, providing intakes close to recommendations. While standard supplements that provide 100% of the EU’s Recommended Daily Allowance are generally suitable, additional vitamin D will need to be provided for those over the age of 65 to achieve intakes of 10 mg per day, as advised by the Department of Health (1).”
Based on: Ruxton C. The role of micronutrients in healthy ageing. Nutrition & Food Science. 2011; 41(6): 420–429.
19 December 2016
1 October 2014
As concentrated sources of micronutrients designed to supplement the normal diet, dietary supplements can be used to balance specific dietary deficits or to ensure adequate intakes. However, in some cases too high an intake of micronutrients can have adverse effects on health or cause undesirable side effects; for this reason it is necessary to define maximum intakes to guarantee the safety of their use in dietary supplements. Since the European legislative authority has not yet established uniform maximum intakes across the whole of Europe, manufacturers of dietary supplements and fortified foods are guided by recommended daily amounts and scientifically recognized upper limits for safe total daily intakes. This also applies to safe intakes for minerals present in the body, whether as macro-elements in concentrations of at least 50 mg per kg dry body weight, or as trace elements (micro-elements) in concentrations of under 50 mg per kg body weight (see also The safety of micronutrients – Part 1: fat-soluble vitamins and Part 2: water-soluble vitamins).
1 December 2014
Optimizing vision throughout the lifespan is a public health priority worldwide, not only because of its central importance to quality of life, but also because of the health care costs associated with the loss of vision in an aging population. Oxidative stress is thought to be a key pathogenic mechanism of compromised vision, and the antioxidant properties of some nutrients show the capacity to modulate disease conditions linked to oxidative stress. Considerable evidence has accumulated showing that vitamins A, C, E, beta-carotene and zinc help support vision and may be protective against the development or progression of some common – especially age-related – eye diseases such as age-related macular degeneration and cataracts. In addition, increased intakes of the carotenoids lutein and zeaxanthin and the omega-3 fatty acid docosahexaenoic acid (DHA) – all concentrated in the eye – have been associated consistently with lower likelihood of sight-threatening conditions. There has also been some promising research with B vitamins in age-related eye diseases and with vitamin A and DHA in the rare disease retinitis pigmentosa (see also Key nutrients for healthy vision).