Lígia Araújo Martini

Prevalence of Vitamin D Insufficiency in Brazilian Adolescents

Background/Aims: Cutaneous sun exposure and dietary vitamin D intake are important determinants of vitamin D status. The objective of the present study was to evaluate the vitamin D status of a group of healthy adolescent students living in Brazil. Methods: One hundred and thirty-six adolescents, 64 boys and 72 girls, aged 16–20 years old, living in a rural town in the state of São Paulo, Brazil, participated in this study. Results: The mean dietary vitamin D intake was 140 (120–156) IU/day [3.5 (3.0–3.9) μg/day]. Only 14.9% of the students met the daily adequate intake recommendation of vitamin D. Only 27.9% practice physical activity outdoors and 17.6% of the adolescents apply sunscreen daily. The mean 25(OH)D concentration was 73.0 (22.0) nmol/l [29.2 (8.8) ng/ml]. Vitamin D insufficiency was observed in 60% of adolescents. Conclusions: The present study suggests that even in a sunny climate like Brazil the prevalence of vitamin D insufficiency in adolescents is high. Most likely this is due to low intakes of vitamin D in this group. Due to the limited extent of natural dietary sources of vitamin D, a policy of vitamin D food fortification should be considered in the future, and in the meantime greater use of vitamin D supplements in this population group should be encouraged to provide the increased amounts of this essential nutrient for optimal health.

Nutrient intakes related to osteoporotic fractures in men and women – The Brazilian Osteoporosis Study (BRAZOS)

BackgroundAdequate nutrition plays an important role in bone mass accrual and maintenance and has been demonstrated as a significant tool for the prevention of fractures in individuals with osteoporosis.ObjectiveThe aim of the present study was to evaluate bone health-related nutrients intake and its association with osteoporotic fractures in a representative sample of 2344 individuals aged 40 years or older in Brazil.MethodsIn a transversal population-based study, a total of 2420 individuals over 40 years old were evaluated from March to April 2006. Participants were men and women from all socio-economic classes and education levels living around the Brazilian territory Individuals responded a questionnaire including self reported fractures as well a 24-hour food recall. Nutrient intakes were evaluated by Nutrition Data System for Research software (NDSR, University of Minnesota, 2007). Low trauma fracture was defined as that resulting of a fall from standing height or less. Nutrient intakes adequacies were performed by using the DRIs proposed values. Statistical analysis comprises Oneway ANCOVA adjusted by age and use of nutritional supplements and multiple logistic regression. SAS software was used for statistical analysis.ResultsFractures was reported by 13% of men and 15% of women. Women with fractures presented significantly higher calcium, phosphorus and magnesium intakes. However, in all regions and socio-economical levels mean intakes of bone related nutrients were below the recommended levels. It was demonstrated that for every 100 mg/phosphorus increase the risk of fractures by 9% (OR 1.09; IC95% 1.05–1.13, p < 0.001).ConclusionThe results demonstrated inadequacies in bone related nutrients in our population as well that an increase in phosphorus intake is related to bone fractures.

Focus on vitamin D, inflammation and type 2 diabetes

The initial observations linking vitamin D to type 2 diabetes in humans came from studies showing that both healthy and diabetic subjects had a seasonal variation of glycemic control. Currently, there is evidence supporting that vitamin D status is important to regulate some pathways related to type 2 diabetes development. Since the activation of inflammatory pathways interferes with normal metabolism and disrupts proper insulin signaling, it is hypothesized that vitamin D could influence glucose homeostasis by modulating inflammatory response. Human studies investigating the impact of vitamin D supplementation on inflammatory biomarkers of subjects with or at high risk of developing type 2 diabetes are scarce and have generated conflicting results. Based on available clinical and epidemiological data, the positive effects of vitamin D seem to be primarily related to its action on insulin secretion and sensitivity and secondary to its action on inflammation. Future studies specifically designed to investigate the role of vitamin D on type 2 diabetes using inflammation as the main outcome are urgently needed in order to provide a more robust link between vitamin D, inflammation and type 2 diabetes.

Current perspectives on vitamin D, immune system, and chronic diseases

Accumulating data support that vitamin D possesses several biological and molecular actions apart from its role in calcium homeostasis. Immune cells express vitamin D receptor and are capable of metabolizing vitamin D. Within this context, experimental studies show that vitamin D modulates immune and inflammatory responses. Epidemiologic evidence linking poor vitamin D status to autoimmune diseases, type 2 diabetes, and cardiovascular disease suggests that insufficient vitamin D may be involved in the etiology of such disorders. Given the impact of immune and inflammatory abnormalities in the development of chronic diseases, including autoimmune disorders, it is possible that vitamin D might reduce chronic disease risk by modulating the immune system.

Role of vitamins and minerals in prevention and management of type 2 diabetes mellitus

Vitamins and minerals play an important role in glucose metabolism, so understanding the impact of vitamin and mineral deficiencies and the potential utility of supplementation is relevant to the prevention and/or management of type 2 diabetes mellitus (DM). This review investigates current evidence for relationships between selected nutrients - vitamin B complex, antioxidants (vitamin A, C, E and carotenoids), calcium, vitamin D, vitamin K, magnesium, sodium, and potassium - and glucose metabolism. The investigation reveals current evidence is not strong enough for supplementation with minerals and vitamins to be recommended on a large scale for the prevention or management of DM. In order to prevent deficiencies and maintain health, the majority of diabetic individuals should receive daily vitamins and minerals within the ranges of recommended values from consumption of natural food sources and/or fortified foods. Further studies including large samples and longer follow-up periods are necessary to ascertain the benefits of mineral and vitamin supplementation to subsets of individuals who are at increased risk for DM or its complications.

Effect of protein intake on bone and muscle mass in the elderly

The aging process is frequently characterized by an involuntary loss of muscle (sarcopenia) and bone (osteoporosis) mass. Both chronic diseases are associated with decreased metabolic rate, increased risk of falls/fracture, and, as a result, increased morbidity and loss of independence in the elderly. The quality and quantity of protein intake affects bone and muscle mass in several ways and there is evidence that increased essential amino acid or protein availability can enhance muscle protein synthesis and anabolism, as well as improve bone homeostasis in older subjects. A thorough evaluation of renal function is important, since renal function decreases with age. Finally, protein and calcium intake should be considered in the prevention or treatment of the chronic diseases osteoporosis and sarcopenia.

Risk factors for recurrent falls among Brazilian women and men: the Brazilian Osteoporosis Study (BRAZOS)

The objective of the study was to estimate the frequency of recurrent falls and identify the main associated risk factors. The BRAZOS is the first epidemiological study performed on a representative sample of the Brazilian population. Anthropometric data, living habits, previous fractures, falls, dietary intake, physical activity and quality of life were evaluated in 2,420 individuals aged 40 and older. Recurrent falls were reported by 15.5% of men and 25.6% of women. Among women, the risk factors significantly associated to recurrent falls were age, previous fracture, sedentary lifestyle, poor quality of life, diabetes mellitus and current use of benzodiazepine. In men, the risk factors were age, poor quality of life, intake of alcoholic beverages, diabetes mellitus, previous fracture and use of benzodiazepine. A greater intake of vitamin D had a protector effect on the risk of recurrent falls. These findings demonstrated the high prevalence of recurrent falls and emphasize that a multidisciplinary approach is necessary to minimize recurrent falls and their consequences, including osteoporotic fractures.

Metabolic osteopathy in celiac disease: importance of a gluten-free diet.

Reduced bone mineral density (BMD) is frequently found in individuals with untreated celiac disease (CD), possibly due to calcium and vitamin D malabsorption, release of pro-inflammatory cytokines, and misbalanced bone remodeling. A gluten-free diet (GFD) promotes a rapid increase in BMD that leads to complete recovery of bone mineralization in children. Children may attain normal peak bone mass if the diagnosis is made and treatment is given before puberty, thereby preventing osteoporosis in later life. A GFD improves, but rarely normalizes, BMD in patients diagnosed with CD in adulthood. In some cases, nutritional supplementation may be necessary. More information on therapeutic alternatives is needed.

Nutritional aspects of the prevention and treatment of osteoporosis

Osteoporosis is a global health problem characterized by low bone mass and microarchitectural deterioration of bone tissue with a consequent increase in bone fragility and susceptibility to fracture. Nutrition plays a critical role in reducing the risk of osteoporosis through its effect on all of these fragility factors, especially on the development and maintenance of bone mass. An adequate calcium, vitamin D and protein intake resulted in reduced bone remodeling, better calcium retention, reduced age-related bone loss, and reduced fracture risk. Recent evidence indicates that a healthy dietary pattern including dairy products (mainly fat free), fruit and vegetables and adequate amounts of meat, fish and poultry is positively related to bone health. Furthermore, mineral and vitamin supplementation should be closely monitored by health professionals since it could have adverse effects and be insufficient to ensure optimal protection of bone health.

Calcium intake and its relationship with adiposity and insulin resistance in post-pubertal adolescents

BACKGROUND Dietary calcium intake has been described as being a negative contributor to adiposity. In adolescents, this relationship is not well established. The objectives of the present study were to compare the calcium intake of normal-weight and obese adolescents and to evaluate its relationship with adiposity and insulin resistance. METHODS A cross-sectional analysis of 96 post-pubertal adolescents; 47 normal weight and 49 obese, mean age 16.6 (SD +/- 1.3) years. Body composition was assessed by dual-energy X-ray absorptiometry. Dietary intake was evaluated using a 3-day dietary record. The biochemical evaluation comprised the measurements of serum lipids, lipoproteins, glucose and insulin. Insulin resistance was calculated using the Homeostasis Model Assessment of Insulin resistance (HOMA-IR). RESULTS The mean calcium intake, adjusted for energy, was lower in obese adolescents, 585.2 (+/-249.9) mg, than in normal weight adolescents, 692.1 (+/-199.5) mg. Only 4% of adolescents had an adequate intake of calcium. Calcium intake was inversely associated with body trunk fat, insulin and HOMA-IR in the obese group. The quartile analysis of calcium intake provided evidence that girls in the highest quartile had decreased adiposity and insulin resistance. CONCLUSIONS This study showed a negative relationship between calcium intake and body fat and insulin resistance, mainly in obese girls, and demonstrates the importance of an increased dietary calcium intake.