Body composition determination by bioimpedance: an update

Nutrition in phenylketonuria

The same basic principles are used to deliver dietary treatment in PKU that was developed sixty years ago. Dietary treatment is undoubtedly very successful, but it has gradually evolved and been guided commonly by individual experience and expert opinion only. There is little international consensus about dietary practice with improvements in specialist dietary products concentrating on taste and presentation rather than nutritional composition. Many areas of dietary treatment have not been rigorously examined. In particular, the amino acid and micronutrient profile of Phenylalanine-free (phe-free) amino acids requires further study. In different formulations of phe-free amino acids, there are variations in the amino acid patterns as well the amount of essential and non essential amino acids per 100g/amino acids. The amount of added tyrosine and branch chain amino varies substantially, and in PKU specifically, there is little data about their relative absorption rates and bioavailability. In phe-free amino acids, there is evidence suggesting that some of the added micronutrients may be excessive and so the source and amount of each micronutrient should be scrutinized, with a need for the development of international nutritional composition standards exclusively for these products. There is a dearth of data about the life-long phenylalanine tolerance of patients or the nutritional state of adult patients treated with diet. There is a growing need to measure body composition routinely in children with PKU and with the rise in childhood obesity, it is important to measure body fatness and identify those who are at greatest risk of 'co-morbidities' of obesity. There is necessity for international collaboration to ensure robust data is collected on many basic aspects of nutritional care to guarantee that diet therapy is delivered to the highest standard.

Nutritional status as marker for disease activity and severity predicting mortality in patients with systemic sclerosis

OBJECTIVE

To assess and analyse nutritional status in patients with systemic sclerosis (SSc) and identify possible associations with clinical symptoms and its prognostic value.

METHODS

Body mass index (BMI) and parameters of bioelectrical impedance analysis (BIA) were assessed in 124 patients with SSc and 295 healthy donors and matched for sex, age and BMI for comparisons. In patients with SSc, BMI and BIA values were compared with clinical symptoms in a cross-sectional study. In a prospective open analysis, survival and changes in the nutritional status and energy uptake induced by nutritional treatment were evaluated.

RESULTS

Patients with SSc had reduced phase angle (PhA) values, body cell mass (BCM), percentages of cells, increased extracellular mass (ECM) and ECM/BCM values compared with healthy donors. Malnutrition was best reflected by the PhA values. Of the patients with SSc, 69 (55.7%) had malnutrition that was associated with severe disease and activity. As assessed by multivariate analysis, low predicted forced vital capacity and high N-terminal(NT)-proBNP values discriminated best between good and bad nutritional status. Among different clinical parameters, low PhA values were the best predictors for SSc-related mortality. BMI values were not related to disease symptoms or mortality. Fifty per cent of patients with SSc had a lower energy uptake related to their energy requirement, 19.8% related to their basal metabolism. Nutritional treatment improved the patients' nutritional status.

CONCLUSIONS

In patients with SSc, malnutrition is common and not identified by BMI. BIA parameters reflect disease severity and provide best predictors for patient survival. Therefore, an assessment of nutritional status should be performed in patients with SSc.

Follow-up whole-body assessment of adipose tissue compartments during a lifestyle intervention in a large cohort at increased risk for type 2 diabetes

PURPOSE

To assess adipose body compartments with magnetic resonance (MR) imaging and MR spectroscopy during a lifestyle intervention program that included optimized nutrition and controlled physical activity in subjects at increased risk for type 2 diabetes to determine factors that may help predict an increase in insulin sensitivity following the intervention.

MATERIALS AND METHODS

This prospective study was approved by the local review board. All participants gave written informed consent. MR imaging and MR spectroscopy were performed in 243 subjects (99 men and 144 women) before and 9 months after enrollment in a lifestyle intervention program. The results of whole-body MR imaging were used to calculate tissue profiles, differentiating between adipose tissue--especially visceral adipose tissue--and lean tissue. The concentration of hepatic lipids and intramyocellular lipids in the anterior tibial and soleus muscles was determined with MR spectroscopy, and insulin sensitivity was estimated by using an oral glucose tolerance test. The Student t test was used to assess differences between groups, and multivariate regression models were used to assess the value of adipose tissue compartments in the prediction of insulin sensitivity.

RESULTS

Compared with women, men had almost twice the amount of visceral adipose tissue and a smaller amount of total adipose tissue (25.9% for men and 36.9% for women) at baseline. In addition, their insulin sensitivity was significantly lower than that of women. The most pronounced changes in adipose tissue were detected for visceral adipose tissue (from 4.9 L to 4.1 L [ie, -15.1%] in men and from 2.3 L to 1.9 L [ie, -15.8%] in women) and hepatic lipids (from 8.6% to 5.4% [ie, -36.8%] in men and from 5.1% to 4.3% [ie, -16.5%] in women). The mean insulin sensitivity improved significantly (from 11.3 arbitrary units [au] to 14.6 au [ie, +29.9%] in men and from 13.6 au to 14.6 au [ie, +7.5%] in women), with 70 of the 99 men (71%) and 84 of 144 women (58%) showing an increase in insulin sensitivity. In men, low concentrations of visceral adipose tissue, hepatic lipids, and abdominal subcutaneous fat at baseline were predictive of successful intervention in terms of changes in insulin sensitivity; in women, only low hepatic lipid levels were significantly predictive of successful intervention.

CONCLUSION

Visceral adipose tissue and hepatic lipids, as assessed with MR imaging and MR spectroscopy, can be significantly reduced during lifestyle intervention. Their baseline values emerged as predictive factors for an improvement of insulin sensitivity.