The effect of Lactobacillus rhamnosus HN001 on mineral absorption and bone health in growing male and ovariectomised female rats

Prebiotics affect mineral absorption, in part by increasing solubility due to short chain fatty acid generation. Prebiotics stimulate the growth of probiotics in the gut and probiotics may affect mineral absorption by similar mechanisms. The objectives of this study were to measure (1) the effect of Lactobacillus rhamnosus strain HN001 (HN001) on mineral absorption in growing male rats and (2) whether HN001 can reduce bone loss and affect bone properties in female ovariectomised (OVX) rats. Study 1: Twenty-two 3-week-old Sprague-Dawley rats were weaned onto a milk powder-based diet supplying 20% protein and 0.5% calcium. After a week, the rats were randomised into two groups: one continuing on the base diet and the other receiving 109 cfu HN001 per day in the diet. After 3 weeks, the animals were housed in metabolic cages for 8 days. Food intake was measured, and urine and faeces were collected for 3 days. Calcium and magnesium balances were calculated. Study 2: Forty 5.5-month-old female Sprague-Dawley rats were ovariectomised or sham-operated and randomised into three groups. The sham (n = 10) and OVX control groups (n = 15) remained on a caseinate-based control diet, while the experimental group (n = 15) received 109 cfu HN001 per day in the diet. After 12 weeks, bone density was measured by dual energy X-ray absorptiometry and bone and blood samples were collected. HN001 improved calcium and magnesium retention in the growing male rats, but due to differences in food intake, data was inconclusive. However, HN001-fed OVX rats had a reduced rate of bone loss and a higher. nal bone density in the spine and femur at week 12 compared to the OVX control group. HN001 may improve mineral bioavailability and have a positive effect on bone mineral density and mineral content. The underlying mechanisms need to be researched.