Determination of the vitamin D status of adults living in the UK and identification of factors influencing the efficacy of dietary intervention

Introduction There is overwhelming clinical evidences that vitamin D plays a significant role in terms of the normal functioning of human body. One of the most common functions of vitamin D is to ensure normalcy in maintaining blood levels of both calcium and phosphate. The two elements are essential for normal bone mineralisation, contraction of muscles, conduction of nerves, and other general body cellular functions. As such, deficiency of vitamin D is associated with various adverse health complications including failure in proper bone development, cancer, and heart diseases (Holick, 2011, p.6). A review of several studies has also established evidence that vitamin D replacement can boots longevity among other health benefits (Gaddipati, et al. 2010). Adequate synthesis of vitamin D3 from the skin, everyday diet and supplements is essential for health of bones. In addition to the well-known role of vitamin D in regulating calcium metabolism, active form of vitamin D is also associated with ant i-proliferative as well as immunomodulatory effects that are linked to several serious conditions such as cancer, metabolic syndrome, cardiovascular diseases, obesity, diabetes, tuberculosis, dementia among other illnesses (Zitterman,et al., 2001). There have been concerns that vitamin D deficiency is significantly increasing in the western nations, and the likelihood of the problem becoming an epidemic in itself worries nutritionists as well as medical practitioners alike (Hypponen and Power (2007). A recent survey in England has revealed a worrying statistics that half of the adult population does not have sufficient levels of vitamin D (Pearce and Cheetham, 2010). The same study also revealed that 16% of this population has experienced severe hypovitaminosis D during winter and spring, with the highest rate being residents of Northern England regions. It is perhaps unsurprising that there have been increasing calls for regular screening during normal health care services. The concerns over vitamin D deficiency has led to a shift over the past decade, with several researchers striving to establish some of the most common risk factors associated with vitamin D deficiency (Holick, 2004). In a study to establish difference in propensity to vitamin D deficiency between metabolically health and unhealthy obese adults, Esteghamati et al. (2004) found out that metabolically healthy obese registered more concentration of vitamin D than metabolically unhealthy obese. This difference persisted even after accounting for body mass index (BMI) and circumference of the individuals’ waists. Further, there was significantly better metabolic status and higher concentration of serum 25-hydro vitamin D among the subjects with metabolically healthy obesity. The researchers also noted that the metabolically unhealthy subjects had higher concentrations of liver enzymes and inflammatory markers. In February 2014, Health & Social Care Information centre released a report on obesity, physical activity, and diet in England, which indicated that obesity cases were on the rise (HSCIC, 2014). The data indicate that there has been a significant increase in the proportion of obese populat ion from 13.2 percent in 1993 to 24.4 percent of men in 2012. Women recorded a similarly high increase during the same period from 16.4 percent to 25.1 percent. Linking this data to relationship between obesity and vitamin D deficiency, it prudent to highlight that vitamin D deficiency prevalence is a point researchers should note with keenness it deserves. The extent to which vitamin D deficiency is a public health problem in Britain is believed to have increased for several reasons ranging from lifestyle to weather patterns. On lifestyle as a factor, Hypponen and Power (2007) states that the sedentary lifestyle in the western world, including Great Britain, leads to vitamin D deficiency, which is exacerbated by a number of other factors including working indoors during daylight hours, high latitude and a mostly cloudy climate in regions such as Manchester. Statistics also indicate that vitamin D dietary intake is much lower in Great Britain compared to other western nations incl uding United States and Canada (Calvo et al, 2005, p.314). The variance in dietary intake of vitamin D between Britain, on the one hand, and United States and Canada, on the other, may be due to the mandatory fortification of both milk and margarine in the USA and Canada. Some of the most common food sources rich in vitamin are fish, liver, fortified margarine and fortified cereals. However, clinical nutritional assessments of natural food items suggest that with the exception of fish and cod liver oil, most natural food stuff contains minimal vitamin D, if any (Brough et al., 2010). Significantly, it is important to note that insufficient natural sources for vitamin D is a risk factor in itself, and should be taken into consideration when plans are put into place to tackle the problem. Moreover, vitamin D supplements’ availability cannot be described as reliable since demand always exceeds supply (Brough et al., 2010). Studies have revealed that there are high rates of vitam in D deficiency all over Great Britain, particularly in the cloudy regions like Manchester and Scotland (Pal et al., 2003). Obesity is a well-known risk factor for vitamin D deficiency, and its high prevalence in Great Britain is likely to affect vitamin D status in the population of high-risk regions such as Greater Manchester. In another nationwide study conducted to investigate the demographic characteristics of white population and possibility of supplements use, it emerged that women and non-obese participants were more likely to use vitamin D supplements (Gaddipati et al, 2010). Similarly, residents of Northern England were found to consume less oily fish, an important source of vitamin D, compared to their Southern counterparts. The study concurs with reports that people living on the Northern England and Scotland have higher risk of hypovitaminosis D (Roy et al., 2007; Holick, 2004). In fact, those who are obese and also live in high-risk regions have a likelihood of having vitamin D deficiency twice as high as other obese people living in other areas of Great Britain. Vitamin D deficiency has also been reported to be prevalent among minority communities living in Great Britain (de Roos et al, 2012). Some ethnic minorities living in Great Britain are more susceptible to vitamin D deficiency than other groups. According to Brough et al. (2010), minority ethnic communities, particularly those who trace their roots to Indian subcontinent and Africa as they tend to suffer from rise in skin pigmentation. They are also found to increase their susceptibility to vitamin D deficiency by wearing clothes that tend to cover their entire bodies and staying indoors longer hours during the day (de Roos et al, 2012; Brough et al., 2010). Other researchers recognise the need to increase vitamin D supplement intake among the minority population, amid report that there are no consistent or routine supply of vitamin D; neither are there recognised screening programs targeting this group (Dealberto, 2006). A study looking at population demographics in the North West has revealed that the region has increasing number older people (North West Regional Assembly Report, 2000). As stated earlier, elderly people are at high-risk of vitamin D deficiency. Clinical studies have investigated age-related decline in vitamin D intake, including rate of skin absorption and response to targeted methods of increasing vitamin D through dietary interventions (Shaw and Pal, 2002). Several other studies have also linked low vitamin D status with people living in low economic status (Dealberto, 2006.). In many of these linkages, the authors cite issues such as poor nutrition, poor lifestyle and inability to afford supplements. For instance, poor nutrition intake is prevalent in regions with high poverty rate, mostly affecting middle aged women of child-bearing age (Brough et al., 2010). According to Brough et al. (2010) a socially deprived population cannot afford some of the basic nutrients essential for normal metabolic function such as vitamin D and thus resort to ‘shortcuts of life’ while exposing their immune system to chronic diseases. Poverty report released by the Greater Manchester Poverty Commission in 2002 identified Manchester as one of the regions with the highest cases of extreme poverty, with 25 percent of its population living in abject poverty (GMPC, 2012). The report further reveal that poor families cannot protect themselves from winter temperature, which makes them stay indoors longer than other UK residence with average annual income. This can only mean that they have higher risk from vitamin D deficiency. OECD report (2014) suggests that the first step in ensuring low income community members in the United Kingdom are protected from lifestyle related diseases is through social interventions. Tests have revealed that modest rise in vitamin D intake of up to 20 Â µg per day for this group can significantly reduce the rate of bone fracture (Hypponen and Power, 2007). The findings have raised focus by agencies and researchers, who have recommended that vitamin D intake for the elderly should raised from the current 5Â µg per day to between 10-20Â µg per day in order to maintain the normal hydroxy vitamin D of 25 (de Roos, 2012, p.6). Considering the need to increase vitamin D intake among the population at risk of vitamin D deficiency, the UK Committee on Medical Aspects of Food Policy (COMA) recommended that people eat at least 280 g of fish per week, with preference to oily fish (de Roos, Sneddon and Macdonald, 2012, p.6). The Scientific Advisory Committee on Nutrition (SACN) endorsed the COMA recommendation, emphasising that this is the bare minimum fish consumption recommended for the average population goal to achieve the desired vitamin D status. However, they acknowledged that this recommendation does not represent the level of fish consumption required for optimal nutritional benefits. The campaign to encourage more UK population, particularly those living in North Western region, should be directed at increasing oily fish intake by at least 280 Â µg per week as statistics indicate that majority of them do not consume enough fish (de Roos, 2012; Holick, 2011; Hypponen and Power, 2007). Although studies (de Roos, 2012; Holick, 2004) have dwelt on the need for multiple interventions ranging from dietary to medical, of more significant for the efficacy of dietary intervention is the need for education among the population on the importance of adopting healthy diet and lifestyle. This is mostly recommended for the high-risk persons including the low-income population, those living in marginally wet and cloudy regions including Manchester, obese, and young women of child bearing age group. References Brough. L., Rees, G., Crawford, M.A. Morton. R.H. and Dorman, E.K. 2010. Effect of multiple- micronutrient supplement on maternal nutrient status, infant birth weight and gestational age at birth in a low-income, multi-ethnic population. British Journal of Nutrition, 104 (3): 437- 445. Calvo, M.S., Whiting, S.J. and Barton, C.N. 2005. Vitamin D intake: a global perspective of current status. J Nutr 135: 310–6. de Roos, B. Sneddon, A. and Macdonald, H. 2012. Fish as a dietary source of healthy long chain n-3 polyunsaturated fatty acids (LC n-3 PUFA) and vitamin D: A review of current literature. Food & Health Innovation Service, available at http://www.abdn.ac.uk/rowett/documents/fish_final_june_2012.pdf. Dealberto, M.J. 2006. Why immigrants at increased risk for psychosisVitamin D insuffiency, epigenetic mechanisms, or bothMedical Hypothesis, Vol. 68, pp. 259- 267. Esteghamati, A., Aryan, Z. and Nakhjavani, M. 2004. Differences in vitamin D concentration between metabolically healthy and unhealthy obese adults: Association with inflammatory and cardiometabolic markers in 4391 subjects. Diabetes & Metabolism, 5 May 2014, Available online at http://www.sciencedirect.com/science/article/pii/S1262363614000469 Gaddipati, V.C., Kuriacose, R. and Copeland R., et al. 2010. Vitamin D deficiency: an increasing concern in peripheral arterial disease. J Am Med Dir Assoc. 11(5): 308-11. Greater Manchester Poverty Commission (GMPC). 2012. Research Report . The Centre for Local Economic Strategies. Holick, M.F. 2011. Vitamin D: a d-lightful solution for health. J Investig Med. 59(6):872-80. Holick MF. 2004. Sunlight and vitamin D for bone health and prevention of autoimmune diseases, cancers, and cardiovascular disease. Am J Clin Nutr 80 (suppl):1678S–88S. HSCIC. 2014. Statistics on Obesity, physical Activity and Diet. Health & Social Care Information Centre, England 26 February 2014. Hypponen, E. and Power, C. 2007. Hypovitaminosis D in British adults at age 45 y: nationwide cohort study of dietary and lifestyle predictors. Am J Clin Nutr, 85(3): 860-868. North West Regional Assembly, 2000. An Aging Population: Impact for the North West. North West Regional Laboratory. Lancaster University. Available at www.northest-england.org.uk. OECD Report. (2014). Society at a Glance 2014 Highlights: United Kingdom OECD Social Indicators. Last accessed on 19 May 2014 at http://www.oecd.org/unitedkingdom/OECD-SocietyAtaGlance2014-Highlights-UnitedKingdom.pdf Pal , B.R., Marshall ,T. and James, C. 2003. Shaw NJ. Distribution analysis of vitamin D highlights differences in population subgroups: preliminary observations from a pilot study in UK adults. J Endocrinol. 179:119–29. Pearce, S.H. and Cheetham, T.D. January, 2010. Diagnosis and management of Vitamin D deficiency. BMJ, 11: 340. Roy D.K, Berry J.L., Pye, SR et al. 2007. Vitamin D status and bone mass in UK South Asia women. Bone 40(1): 200-4. Epub 2006 Sep 6. Shaw, N.J and Pal, B.R. 2002. Vitamin D deficiency in UK Asian families: activating a new concern. Arch Dis Child, 86: 147-149, Available at http://adc.bmj.com/content/86/3/147.full Zittermann A, Schleithoff SS, Koerfer R. 2005. Putting cardiovascular disease and vitamin D insufficiency into perspective. Br J Nutr 94: 483–92.