Abstract
The health-related benefits of a high consumption of fruit & vegetables on a variety of diseases, including skeletal health have been advocated by health organisations. The effect of high acidity, weight-reducing diets on bone health also remains undefined This project involved two key aspects: a population-based study and an intervention study. The principal aims of the population based study were to: (i) estimate the acid/alkaline potential of the diet in a representative group of British elderly from National Diet and Nutrition Survey (NDNS) datasets using several validated algorithms for calculating the potential renal acid load (PRAL) and estimated net endogenous acid production [NEAP], (ii) compare and characterise the aforementioned algorithms by specific nutrients/food groups likely to influence dietary acid load in the abovementioned population group and a representative sample of Irish adults (18-64 years) using North South Ireland Food Consumption Survey (NSIFCS) datasets. The principal aims of the intervention study were to: (i) quantify the dietary acidity characteristics of a low carbohydrate diet (LCD) versus a high fruit and vegetable (F&V) weight loss group and a weight maintenance (WM) control group using PRAL and estimated NEAP (ii) determine the short-term (6-months) of the aforementioned groups on bone turnover markers. PRAL and estimated NEAP were measured using the aforementioned datasets. Values for both algorithms increased significantly with increasing age (P<0.001), except in the oldest age group for the elderly British population. Higher intakes of fruit and vegetables resulted in significantly lower dietary loading, conversely protein, meat and fish intakes were significantly associated with higher dietary acidity. A total of 68 overweight/obese (BMI 27-40 kg/m2) men aged 21-65 years were recruited to follow either one of two diets: a LCD versus a F&V weight loss programmes and a WM group. Dietary intake, anthropometries, blood pressure, and fasting blood and urine samples were measured. Results showed the weight reducing diets were effective with weight loss and those subjects on the LCD diet had significantly higher levels of acidity. There was a significant decrease in dietary acid loading in F&V group at 6 months. No differences were found for markers of bone turnover in the LCD group compared to the other groups. This study did not demonstrate a detrimental effect of high acidic-weight reducing diets on bone turnover markers. Further work is urgently required to examine the potentially detrimental effect of these diets in women as well as the effect of high F&V intakes on bone health indices.