Trends and nutritional status for magnesium in Taiwan from NAHSIT 1993 to 2008.

Data from nationwide population-based nutrition surveys in Taiwan were used to investigate trends and nutritional status for magnesium from 1993 to 2008. Dietary magnesium intake was estimated from 24-hour dietary recalls. Serum and urinary magnesium were also measured. In Nutrition and Health Survey in Taiwan (NAHSIT) 2005-2008, average magnesium intake was 305 mg and 259 mg for adult males and females, respectively, which is equivalent to 82-85% of relevant Taiwanese Dietary Reference Intakes (DRIs). After correcting intra-individual variation, 74-81% of adult subjects' dietary magnesium was estimated as sub-optimal. Mean serum magnesium concentration was 0.866 mmol/L and 0.861 mmol/L for the males and females, respectively. The prevalence of low serum magnesium (<0.8 mmol/L) was 12.3% and 23.7% for the males and females, respectively. There was positive association among dietary magnesium, blood magnesium, and urinary magnesium/creatinine ratio. From NAHSIT 1993-1996 to NAHSIT 2005-2008, dietary magnesium significantly increased (p<0.05), the blood magnesium and urinary magnesium/creatinine ratio decreased (p<0.05). The findings suggest that the relationships between dietary magnesium and biochemical markers among different nutrition and health surveys are not straightforward and need to be further clarified.

Thiamin and riboflavin status of Taiwanese elementary schoolchildren.

In The Nutrition and Health Survey of Taiwan Elementary School Children (NAHSIT Children 2001~2002), erythrocyte activity coefficients of transketolase (ETKAC) and glutathione reductase (EGRAC) were chosen as indices for assessing the functional status of thiamin and riboflavin nutriture. Mean values of the ETKAC for boys and girls, both of which were in a normal range, were 1.07+/-0.00 and 1.06+/-0.01, respectively. The respective prevalence rates of marginal and deficient thiamin states were 10.4% and 7.8% for boys and 9.3% and 7.3% for girls. Mean values of the EGRAC were 1.18+/-0.00 for boys and 1.19+/-0.01 for girls, both of which showed an increasing trend with age. The respective rates of marginal and deficient riboflavin states were as high as 32.5% and 3.5% for boys and 35.9% and 4.5% for girls. The marginal and deficient riboflavin statuses of Taiwanese schoolchildren were associated with a low frequency of dairy food consumption and an elevated risk of anemia.

Magnesium deficiency and its lack of association with asthma in Taiwanese elementary school children.

The purpose of this study was to investigate magnesium nutritional status and its association with asthma in elementary school children (1277 boys and 1109 girls) participating in the Nutrition and Health Survey in Taiwan (NAHSIT children 2001-2002). Dietary magnesium intake was based on 24-hour dietary recalls. Serum magnesium was measured. Average magnesium intake was 247 mg and 228 mg for the boys and girls, respectively, which is equivalent to 135-123% of the relevant Taiwanese Dietary Reference Intakes (DRIs). Mean serum magnesium concentration was 0.87 mmol/L and 0.86 mmol/L, respectively. The prevalence of serum magnesium <0.8 mmol/L was 10.5-13.5% in both gender in our sample of elementary school children. In Taiwan, asthma was diagnosed in about 5.8% and 4.7% of boys and girls, respectively. In this study, there were no associations between asthma prevalence, dietary magnesium and serum magnesium concentration. In about 40% of our sample of school children, however, dietary magnesium may be suboptimal. This deficit should be targeted though improved intake of magnesium-rich foods such as whole grains, green vegetables and soybean products, particularly in Taiwanese school children whose dietary intakes are below the DRIs and/or who have low serum magnesium levels.

Prevalence of thiamin and riboflavin deficiency among the elderly in Taiwan.

The purpose of this study was to perform biochemical assessments of the nutritional status of thiamin and riboflavin in the 2379 elderly persons (1213 males, 1166 females) participating in the Elderly Nutrition and Health Survey in Taiwan (1999-2000) (Elderly NAHSIT). Through analysis of the data we aimed to investigate possible factors related to the prevalence of vitamin deficiency. Activity coefficients of erythrocyte transketolase and glutathione reductase (ETKAC and EGRAC) were the chosen biochemical indicators for thiamin and riboflavin status. The results showed that 14.7% of men and 11.9% of women were marginally thiamin deficient, and 16.5% of men and 14% of women were thiamin deficient. The prevalence rates of marginal riboflavin deficiency were 25.7% for males and 20.1% for females, and the deficiency rates were 6.6% for elderly males and 4.1% for elderly females. Although the average dietary thiamin and riboflavin intakes reached 146%-164% of Taiwan RDAs, the percentage of senior citizens whose thiamin or riboflavin dietary intakes were less than EARs (equivalent to 83.3% of RDAs) was around 30% for males and 40% for females. Some contributing factors to the significant prevalence of thiamin and riboflavin deficiencies are discussed in this article.

Magnesium status and association with diabetes in the Taiwanese elderly.

The average dietary intake of magnesium is below recommended dietary allowances in many affluent Western countries. Prolonged low magnesium intake tends to result in hypomagnesaemia which might increase the risk of chronic diseases in elderly people. A national population-based cross-sectional nutrition survey, the Elderly Nutrition and Health Survey in Taiwan (1999-2000), was used to investigate the magnesium status and association with diabetes in the Taiwanese elderly. Dietary magnesium intake was based on 24-hour dietary recalls. Blood biochemical parameters including plasma magnesium and blood glucose were also measured. Average magnesium intake was 250 mg in men and 216 mg in women, which is equivalent to 68-70% of relevant Taiwanese Dietary Reference Intakes. The mean plasma magnesium concentration was 0.903 mmol/L in men and 0.906 mmol/L in women. The prevalence of a plasma magnesium level of <0.7 mmol/L was 0.7-0.9% in the elderly, and that of <0.8 mmol/L was 8.0-9.1%. Elderly vegans had a significantly lower magnesium intake than ovo-lacto vegetarians and non-vegetarians. Diabetic men and women had significantly higher blood glucose levels than non-diabetics. The risk of diabetes was elevated 3.25 times at plasma magnesium levels<0.863 mmol/L. There was an inverse association between plasma magnesium concentration and the prevalence of diabetes. However, no association was found between diabetes and low dietary magnesium. Taiwanese elderly persons had suboptimal levels of dietary magnesium intake, which although may be sufficient to avoid overt magnesium deficiency, may not be sufficient to reduce the risk of diabetes in the elderly. Further prospective study is required to help explain the differential results between dietary and plasma magnesium levels.

Iron status of the Taiwanese elderly: the prevalence of iron deficiency and elevated iron stores.

Iron status, prevalence of iron deficiency and elevated iron stores, and the effect of gastrointestinal ulceration on iron status in free-living Taiwanese elderly persons were all assessed in a nationally representative, cross-sectional nutrition survey--the Elderly NAHSIT. The survey included blood measurements of iron indices. Data were collected from 1202 elderly men and 1152 elderly women aged 65 years and older. Multiple iron measures, including serum ferritin (SF), transferrin saturation (Tsat), and hemoglobin were used to evaluate the prevalence of iron deficient erythropoiesis (ID) and iron deficiency anemia (IDA). Despite no routine practice of iron fortification in Taiwan, elderly subjects had a low prevalence of ID and IDA. The prevalence of ID was 2.3% in men and 1.4% in women. The prevalence of IDA was 2.5% in men and 2.0% in women. In contrast, 15.7% of men and 9.8% of women had elevated iron stores as diagnosed by SF>300 microg/L. Subjects with a history of gastrointestinal ulceration had significantly lower serum ferritin than those without ulcers, but the prevalence of anemia, ID and IDA was unaffected. In conclusion, elderly people in Taiwan are an iron-replete population with a high prevalence of elevated iron stores and a low prevalence of iron deficiency.