- Comparative effects of yoghurt (enriched with non-pathogenic lactic bacterial) and milk consumption on immunocompetence in a healthy population;
- Comparative effects of yoghurt (enriched with non-pathogenic lactic bacteria) and milk consumption on immunocompetence and on nutritional recovery on two malnourished groups :
- young patients (12-18 years old) suffering from anorexia nervosa (eating disorder increasingly seen in developed countries);
- malnourished African children (4-24 montsh).
- According to STD programme, within general objectives, we tried to establish the role played by fermented dairy products on immune capacity and thereby on nutritional status and recovery.
- Thirty patients with anorexia nervosa (aged 10-19- were tested) in a 10 weeks follow-up study. The patients were divided in two groups depending on their dairy intake of (1) milk or (2) yoghurt (3/day). Calories supplied by milk or yoghurt were similar. The rest of the dietary calories supplied was similar in both groups. Measurements were carried out in three stages :
- at the admission to the hospital;
- after six weeks;
- after ten weeks of the admission.
- The results were compared with 35 young women's volunteers matched by age, sex and socio-cultural level, who were also divided in two groups like the anorexic patients.
- Regarding food habits of the patients tested, 13% and 19% of patients in groups 1 and 2, respectively suffered from vomiting.
- None of the patients had menstruation at the beginning of the study. 25% and 17% of patients receiving yoghurt or milk therapy, respectively recovered menstruation at the end of the study. Diarrhea symptoms after refeeding decreased in the group with yoghurt therapy.
- The dietary profile for both groups of patients was similar and showed a significant higher percentage of carbohydrates and lower percentage of lipids in comparison with both groups of controls.
- In relation to anthropometry, as expected, no modifications were found between both groups of anorexic patients in each stage. However, in both groups of patients, there was a significant increase of weight, BMI and IBW percentage in stage 2, which remained at the same level in stage 3, in comparison with stage 1. Despite the fact that there was an increase of ponderal values in anorexi nervosa patients, all the parameters were lower than in controls. BMI values did not reach 19, the lowest level necessary to be within the normal range.
- Haematological parameters of anorexia nervosa patients were within the normal range in both groups, however, all of them showed values below controls. In relation to leukocyte profile, those patients submitted to the yoghurt therapy showed higher eosinophil levels at stage 2, while eosinophil counting was higher in patients undergoing milk intake at stage 3. Regarding lymphocyte subset percentages, significant differences were found in stages 2 and 3, in comparison with stage 1. In general, there was a better situation for those patients under yoghurt therapy. Serum immunoglobulins (Ig G, A and M) and C3 and C4 complement factors were significantly higher in those patients with yoghurt therapy.
- Yoghurt intake on stimulation of immune response was investigated on Peyer patches, spleen and blood. Interferon-gamma, lymphocyte proliferation and the rate of different immunocompetent cells were evaluated.
- The study was carried out in Wistar-Furth female rats aged 8 weeks that were submitted to a semi-sinthetic diet enriched with yoghurt or milk (35%) for 4 weeks. Immunocompetent cells, previously removed, were cultured in presence of Con A or yoghurt bacteria (Lactobacillus bulgaricus and Streptococcus thermophilus). Interferon-gamma was measured in the supernatants by ELISA and the immunocompetent cells were determined by flow cytometry.
- Yoghurt bacteria were capable to stimulate Interferon-gamma both in Peyer platches and spleen, and in addition induced cell proliferation in Peyer platches, spleen and blood. However, no modifications were found in immunocompetent cell rates, except B lymphocytes of Peyer platches, which increased after yoghurt intake.
- Regular consumption of lactic bacteria induced an increase in non-specific responses against mitoges (ConA), which could suggest an important role of non-pathogen bacteria by improving immunological balance as well as by maintaining host-resistance against pathogen agents. This finding may be significant especially in malnutrition or anorexia nervosa patients where the immune system is depressed.
- In order to evaluate the effect of nutritional refeeding on Interferon-gamma production in malnourished children, 15 infants aged among 6 and 30 months with a weight/height between 60 and 80% (NCHS tables) were admitted to the Paediatric Hospital in Rabat (PO) until they reached 90% of their weight/height ratio (P1). Hospitalisation period average was 30 days. During this period, children received fermented milk diet with a caloric density of 100 cal/100 ml in addition to a vitamin and mineral supplementation. The consumption was 100 cal/kg/d for 10 days and 150-200 cal/kg/d there after.
- In addition, an iron supplementation (100 mg/d) was included in the diet after the 10th day of hospitalisation.
- Blood mononuclear cells were isolated and cultured with lactic bacteria Lactobacillus bulgaricus and Streptococcus thermophilus for 72 hours. The cell-free supernatants from cultures were assayed for Interferon-gamma by ELISA. The samples were collected in PO and P1.
- Although iron supplementation was administrated to the children, their haemoglobin values, which were lower than 11 g/dL in PO, only reached normal levels 3 months after the admission in hospital. Interferon-gamma production in malnourished children was lower than 10 pg/mL in PO. After refeeding (P1) Interferon-gamma production was higher than 150 pg/mL.
- Conclusion : the low haemoglobin values found in the malnourished children did not affect Interferon-gamma production after refeeding. Children showed a good tolerance when yoghurt was included in the diet. Yoghurt intake enhanced Interferon-gamma production. Thus, it would be important to stress the fact that this cytokine production may act as an immunological protection against pathogen micro-organisms in infants who are particularly sensitive to infections since they are malnourished.
- One ot the causes of the increased susceptibility to infectious disease of malnourished individuals is an impaired immune function. In addition, immunocompetence has been shown to be depleted by infection and to be a sensitive and functional measure of the nutritional status. This work was aimed at assessing the effect of yoghurt (enriched with non-pathogenic lactic bacteria) consumption on immune capacity and thereby on nutritional status and recovery in three groups :
- control, consisting of 50 healthy subjects (12-18 years old);
- twenty patients (12-18 years old) suffering from aenorexia nervosa (eating disorder increasingly in developed countries);
- twenty malnourished African children (4-24 months).
- Each group was divided into two subgroups :
- 300 ml/day yoghurt consumption during 2 months;
- 300 ml/day milk consumption during 2 months.
- Dietary intake and anthropometric parameters (weight, height, body mass index, ideal body weight percentage, skin folds) were measured. The following immunological parameters : lymphocyte proliferation, B lymphocytes (CD19), T lymphocyte subsets (CD2, CD3, CD4, CD8), NK lymphocytes (CD57), serum C3 and C4 complement factors and interferon production were evaluated.
Funding SchemeCSC - Cost-sharing contracts