Changes in health risk profile after a 5-months dietary intervention focusing on increased intake of fruits, vegetables and whole grain bread among young male adults

Abstract

The consumption of fruits, vegetables and whole grain bread and subsequently the intake of folate among young men is generally low. Low concentrations of folate, vitamin B2 (riboflavin), vitamin B6 and vitamin B12 have been related to an elevated concentration of total homocysteine in plasma (p-tHcy) which is a well-known risk factor for cardiovascular disease (CVD).<br> The aim of this project was to investigate the health risk profile of young male adults from different socio-economic groups, and possible changes in this profile after a dietary intervention with focus on an increased intake of fruits, vegetables and whole grain bread. The effect of the dietary intervention was studied with a special focus on changes in dietary intake of B-vitamins and changes in the concentration of p-tHcy and related metabolites. In addition, weight, height and serum lipids were measured before and after the intervention. In order to interpret the data on folate intake in the dietary intervention study, another objective was to study the retention of folates in foods after treatment commonly used in Norwegian military messes. The dietary intervention study with duration of 5 months included 541 male recruits from the Norwegian National Guard, Værnes and 209 male recruits from the Norwegian Army, Heggelia. A combination of strategies was used in order to increase the intake of fruits, vegetables and whole grain bread during the intervention period, including nutrition information and increased availability of these food items. The baseline results of the dietary intervention study demonstrated a high prevalence of overweight/obesity (34.8%) and low physical fitness among young male adults (Paper I). The baseline data also showed that a total of 24.8% of the young men had p-tHcy concentration >15 μmol/l (Paper II). On the other hand, serum lipid concentrations were within the normal range among most (98.8%) of the young men participating in the study (Paper I). This study also showed that paternal education was inversely associated with BMI and the concentration of total cholesterol and LDL. In addition, this study showed that fathers with higher education have a positive influence on young male adults’ behaviour pattern and subsequently a positive effect on BMI and lipid profiles. On the other hand, the educational level of the mothers was not related to any of the selected health parameters in young male adults. An inverse relationship between the running performance and the concentration of triacylglycerol was shown. Furthermore, men with low BMI (both high and low fitness) had a better lipid profile than those with high BMI/low fitness. Men with high BMI/high fitness had a better lipid profile than those with high BMI/low fitness. Our results indicate that young men, especially those with low parental education and high BMI, should be considered as an important target group for health promotion efforts. The dietary intervention resulted in a significant increase in the total consumption of vegetables, fruits, berries and juice (FV; +24%) and of whole grain bread (+29%) among the young male adults (Paper III). In accordance with these findings, the estimated total intake of dietary fibre and folate, as well as the relative contribution of folate intake from vegetables, fruits and whole grain bread, increased significantly during the study period. The dietary intervention also resulted in a significantly reduction in the concentration of p-tHcy (-10%), cysteine (p-cys; -6%) and flavin mononucleotide (FMN; -11%), and an increased concentration of vitamin B2 (+23%) and flavin adenine dinucleotide (FAD; +10%). The change in p-tHcy concentration was inversely related to the serum concentration of folate and positively related to the concentration of p-cys and FMN in plasma (Paper II). Further, a significant association was found between an estimated increase in dietary intake of folate from bread and a decrease in p-tHcy concentration (Paper III). The retention of folates was measured in vegetables after processing methods commonly used in the Norwegian military messes, including boiling, steam boiling, sous-vide, oven-baking, microwaving and blanching of vegetables (Paper IV). Only blanching of peas, boiling of potatoes and oven-baking of unpeeled potatoes caused a significant reduction in folate content. Further, this study showed that there were no significant losses of folates after subsequent storage and reheating of vegetables. When estimating the intake of folate during the intervention period, losses of folate due to blanching of vegetables was taken into consideration. The other methods of processing that caused significant reduction in folate content were rarely used during the intervention period. Thus, it is not likely that the reported intake on folate during the dietary intervention study is overestimated due to losses of folates after processing. In conclusion, the results from the present study demonstrated that a 5-months dietary intervention with focus on increased intake of vegetables, fruits and whole grain bread had favourable effect on the concentration of p-tHcy and its metabolites.