Nutrition

Nutritional problems, especially in women and children, continue to be widely prevalent in the country in spite of many nutrition oriented programmes being implemented by the Govern-ment of India. In addition, with increased life expectancy the nutrition problems of the elderly also need attention. To identify the priority areas for research for finding out effective, practical, economically viable and sustainable solutions for the plethora of nutrition related problems affecting people and to prepare project proposals in a multicentre mode, the Council organised a series of national and international workshops and expert group meetings. The areas identified include development of simple biochemical tests for detection of micronutrient deficiencies, the development of a nutritional surveillance system, identification of foods rich in micronutrients, nutritional problems of aged such as osteoporosis, development of intervention strategies to control undernutrition in children up to 2 yr. of age, and prevalence of low birth weight babies and interventions for their growth and development. The Council has also taken steps to revise the recommended dietary allowances (RDA). The research activities related to nutrition were mainly carried out by the National Institute of Nutrition (NIN), Hyderabad and complemented by its three centres i.e. Food and Drug Toxicology Research Centre, National Centre for Laboratory Animal Sciences and National Nutrition Monitoring Bureau (NNMB). The Institute continued to focus its research activities to address and find solutions to various unresolved issues in the field of nutrition.

COMMUNITY STUDIES

First Repeat Survey of Tribal Population

The National Nutrition Monitoring Bureau (NNMB) conducted a repeat survey for the diet and nutritional assessment of the tribal populations living in the areas covered by Integrated Tribal Development Agency by visiting the villages that had been surveyed earlier. The results revealed that there was a reduction in the extent of severe undernutrition among preschool children with improvement in their height and weight. There was also a marginal increase in the intake of cereals and millets at individual level.

Nutritional Status of Adolescents

The data on adolescent girls, collected through NNMB surveys during 1996-97, were analysed to assess their current diet and nutritional status. The data were also compared with that obtained in 1975-79 from the same villages. There was an increase in the intake of cereals and millets over the past 20 years among the adolescents. Secular changes in height and weight were observed with an increase of about 2.5 to 3.5 cm and 1 to 1.5 kg respectively. The extent of undernutrition as measured by weight for age and stunting (low height for age) also showed a decline during the current survey as compared to 1975-79.

Diet and Nutritional Status of the Elderly

The health and nutritional status of the aged has been receiving considerable attention in recent years. In view of this, data collected on the elderly during the 1996-97 NNMB surveys and the district profile surveys conducted in 1994 in non-NNMB states of Punjab, Haryana, Himachal Pradesh and Assam were analyzed and compared with that of the 1975-79 NNMB surveys. The results showed that the consumption of cereals and millets was more than the RDA in all the age and gender groups. Except in the age group of 80 yr and above, the consumption of energy has improved over a period of time. The extent of chronic energy deficiency (CED) appeared to be higher among the aged population than their younger adult counterparts. There was a considerable reduction in the prevalence of CED as compared to 1975-79.

Micronutrient Status and Mental and Physical Performance of School Children Supplemented with a Special Nutritional Beverage

A double blind randomised placebo controlled study is in progress to evaluate the impact of supplementation of a cocktail of micronutrients in the form of a specially fortified beverage on the physical and mental development of school children. Analysis of base line data indicated that the boys achieved higher IQ as compared to girls.

Boys >10 yr receiving the special nutrition beverage achieved significantly higher verbal and performance quotients compared to their counterparts receiving a placebo. In girls receiving the supplement, significant differences were found in all age groups. The study also revealed that nutritional status and height influenced IQ as better nourished (>75% weight for age) boys and girls in the supplemented group scored higher IQ scores than children in the placebo group. Aspects related to bone density were also studied. The base line whole body mineral content and the density at the neck of the femur were not different in the two groups while there was a significant difference between boys and girls. However, all values were much less than those reported in the Western studies. The micronutrient status in several children in this study was found to be inadequate.

Low Cost Nutritious Supplements

Since red palm oil (RPO) is a rich source of b-carotene, NIN in collaboration with AP Foods, has developed a RPO (carotino) fortified ready-to-eat food as a nutritious supplement for children. Preliminary studies showed that the stability and acceptability of the product were satisfactory.

ENERGY METABOLISM

Sports Nutrition/Work Physiology

Energy expenditure in sports persons involved in different athletic events, such as sprinters, and middle and long distance runners, showed changes from transition to competition phase, based on the intensity of training they received. Therefore, contrary to the current practice of giving uniform ration to all the sports persons all through the season, it is essential to formulate diets to meet the nutritional demands of participants in each sport so as to maintain optimal body composition and achieve optimal performance during competitions.

NUTRITION AND INFECTION

Serum Transferrin Receptor in Children suffering from Infections

To define the iron status in children, normal levels of serum transferrin receptor (STfR) were determined. In addition, the effect of infections on STfR was evaluated. The mean serum STfR was 6.08.48 mg/l in children who had haemoglobin levels more than 11 g/dl, similar to that reported in literature for healthy children. Using this value as the cut-off level, it was observed that more than 50% of children having Hb more than 11 g/dl also had elevated levels of the receptor, thus identifying the wide prevalence of iron deficiency in children. On the other hand, ferritin, which was also estimated, failed to identify even severe anaemia. Mean receptor levels showed a significant negative correlation with Hb levels while ferritin had no correlation with Hb or STfR. Hence, unlike Hb which diagnoses only anaemia, STfR appears to be a good indicator to assess iron stores in preschool children (Fig.14).

STfR was determined in preschool children who attended the hospital for various infections. They were followed up at 15-30 days after the infection. No difference in mean receptor levels was found in children with or without infection with similar haemoglobin levels, thereby indicating that in general, STfR is a good indicator of iron status even in the presence of infection, unlike ferritin which shows an acute phase response. The percentage of children having anaemia and elevated STfR levels was similar. However, STfR values returned to basal level by 30 days after infection. These observations suggest that anaemia of infection is due to iron deficiency which could be due to lack of storage iron or non-mobilization of stored iron in the non anaemic children. These results emphasise the importance of controlling infections for improving iron status of children.

Outcome of Acute Bacterial Meningitis in relation to Nutritional Status in Children

The role of nutritional status and secretion of TNF-a in children suffering from acute bacterial meningitis and the outcome of the disease was determined. Bacterial isolation was found to be positive in 76% of CSF samples with Streptococcus pneumoniae being the most common organism. Neisseria meningitidis, Haemophilus influenzae, Escherichia coli and Streptococci also contributed to meningitis. TNF-a was detectable in 69% of all cases and children with S.pneumoniae, N.meningitidis and H.influenzae as causative organisms had higher levels of TNF compared to the others. Though TNF levels were similar among children with various nutritional grades, the percentage of children producing the cytokine was higher in severe protein energy malnutrition group. Twenty two per cent of the children died and 40% recovered with sequelae. Severely malnourished children had significantly higher adverse outcome compared to better nourished groups. S.pneumoniae contributed to nearly 50% of deaths. Nutritional status and the causative organism appear to contribute to the outcome of acute pyogenic meningitis in children. However, TNF did not significantly influence the outcome. Similarly, nutritional status had no effect on levels of TNF.

MICRONUTRIENTS AND TRACE ELEMENTS

Trends of Xerophthalmia from 1980-1999

The data collected from the records of the Niloufer Hospital for Women and Children during 1980-99 on the trends of severe vitamin A deficiency manifesting as blindness or potentially blinding corneal lesions revealed that 540 children with corneal lesions attended the hospital. On an average 22 to 28 patients were seen per year between 1980 and 1999. The occurrence of corneal lesions was maximum among children aged 1-3 yr followed by those between 3 and 5 yr. Since vitamin A deficiency is still prevalent in some parts of the country, there is a need to target the under-fives and control the scourge of vitamin A deficiency using innovative methods.

Effects of Food based Vitamin A Supplementation during Pregnancy on Maternal and Child Health

With increase in realization of the importance of vitamin A status in maternal and child health, a cross sectional study was conducted among pregnant women during their third trimester to assess the extent of the problem of clinical and subclinical vitamin A deficiency and relate it to the pregnancy outcome. Night blindness was observed in 5% of the women and about 60% of them had serum retinol levels less than 30 mg/dl. Women with night blindness and those with low retinol levels had a significantly higher occurrence of pregnancy induced hypertension, pre-term deliveries and asphyxiated babies. These results suggest the need to undertake in depth studies to explore the role of vitamin A status on maternal health and pregnancy outcome.

Molecular Mechanisms of Immuno-suppression in Severe Protein Energy Malnutrition

mRNA gene expression for cytokines IL2 and IL4 and cytokine profile of lymphocyte culture supernatants for IL2 were examined in children suffering from anaemia and compared with healthy non anaemic children aged 1-5 yr. Healthy children had mRNA expression for IL2 and IL4 whereas anaemic children had it only for IL4. IL2 levels were undetectable in their culture supernatants. Since anaemia is widespread among children, these observations are important, particularly in relation to the ongoing immunisation programmes involving newer vaccines.

Mineral and Trace Element Contents of Foods

Apart from reassessing the mineral and trace element composition of commonly consumed plant foods, foods of animal origin were also analysed using atomic absorption spectrophotometer. It was found that country hen eggs had significantly higher amounts of trace minerals like calcium, phosphorus, copper and manganese as compared to eggs of hens bred in poultry farms.

Transferrin Receptor

The indigenous sandwich ELISA developed at the NIN for the quantitation of serum transferrin receptor (STfR) has been validated in adolescent girls receiving 60 mg of iron supplement for 100 consecutive days. The changes in iron status correlated well with STR and not with serum ferritin. The results of the study confirmed that the indigenous sandwich ELISA technique developed for STfR is a good indicator of iron status.

DIET AND NON-COMMUNICABLE DISEASES

Studies on Fenugreek Seeds

Galactomannan, the soluble dietary fibre present in the fenugreek seeds, was isolated and its effect on the blood glucose and cholesterol levels of obese rats (WNIN/GR-ob) assessed. Incorporation of galactomannan into the control diet at 2.5 and 5.0% levels could significantly decrease plasma glucose and cholesterol levels at the end of 9 weeks both in males and females compared to animals receiving control diet alone.

Biochemical and Metabolic Studies with Sesame Lignans

The high oxidative stability of sesame oil is attributed to the lignans viz., sesamol (S1), sesamin (S2) and sesamolin (S3). S2 and S3 are present in seeds and oils. On heating the oils to frying temperature, S1 is formed. The antioxidant properties of S1 (Sigma Co.), S2 and S3 (isolated and crystallized at NIN) in comparison to BHT and tocopherols (a and g) were studied in in vitro enzymatic (cumene hydroperoxide induced) and non enzymatic (iron-ascorbate induced) lipid peroxidation systems. The antioxidant activity in cumene hydroperoxide system was in the following order : BHT>aT = gT>S1>S2>S3. The antioxidant properties of lignans in combination with tocopherols showed enhanced inhibitory effects. In the non-enzymatic system, only S1 had inhibitory effects. However, sesame lignans in combination with tocopherols enhanced the inhibitory effects in the non-enzymatic lipid peroxidation system. These findings suggest that sesame lignans can potentiate the antioxidant properties of tocopherols and contribute to their beneficial role as dietary antioxidants.

FOOD CHEMISTRY

Nutrient Composition of Foods

The analysis of total lipid and individual fatty acid contents of selected fresh fruits showed that they contain <1 % total lipids. The a-linolenic acid (ALNA) content is higher in plum, papaya and guava (0.4%) as compared to other fruits (0.2%). On an average about 400 g of fresh fruits provide ~0.1 g ALNA. It was reported earlier that on an average ~60g of green leafy vegetables or ~400g of other vegetables provide 0.1 g of ALNA. Thus, fruits and vegetables can contribute to increasing the n-3 poly unsaturated fatty acid intake in addition to providing several other nutritional benefits.

Fats in Bakery Products

Vanaspati is widely used in the preparation of bakery foods. The data obtained show that biscuits furnish ~12% lipids, ~5% saturated fatty acids (SFA) and 4% trans fatty acids (TFA). Thus, consumption of 7-10 biscuits would furnish about half of the upper safe limit of SFA and TFA together.

FOOD AND DRUG TOXICOLOGY

Food Safety

Application of HACCP to Paneer

The Hazard Analysis Critical Control Point (HACCP) approach which is now well accepted as the best preventive strategy in food safety and quality to prevent food-borne hazards was used for the toxicological evaluation of Paneer (cottage cheese). After identifying the critical control points (CCP) in the manufacturing process, it was found that the microbiological contamination of the final product could be considerably reduced by intervention strategies like improving the personal hygiene of the food handlers.

Ochratoxin in Coffee

Studies on the occurrence of ochratoxins in Indian coffee revealed that although ochratoxin A is present in Arabica, cherry and monsoon coffee samples, its level is well below the limit of 5 g/kg which is considered by the European Union as a safe limit.

Antinutritional Factors in Wild Legume Cassia tora

Studies on the seeds of wild legume Cassia tora indicated the possibility of extracting the gum from the seeds in large quantity by a simple process and its use as a thickener in food products. The seed germ meal obtained as a bye product of gum extraction though rich in protein is found to contain antinutritional factors. A detoxification method to remove antinutritional factors has also been evolved. The studies on protein efficiency ratio (PER) and short term toxicity indicated that the detoxified germ could be used as animal feed ingredient.

Analysis of Argemone Oil in Adulterated Oils

A study carried out in collaboration with Director General of Health Services, New Delhi, on validation and harmonization of analytical method for quantitation of argemone oil in adulterated vegetable oils revealed the efficacy of the method in detecting adulteration. However, in the case of non-edible oils like Karanjia oil, the analytical method gave false positive results.

Drug Toxicology

Biomarkers of Genotoxicity : Antimutagenicity of Heated Garlic

Earlier studies at NIN have demonstrated the antimutagenic property of garlic in rats exposed to benzo(a)pyrene. In order to verify whether this property is still retained after subjecting the garlic to cooking, a study with cooked, boiled and unboiled garlic was undertaken with S.typhimurium TA 98 as tester strain. The results showed that the antimutagenic principles in garlic are not destroyed by heat treatment.

Studies on Medicinal Plants from North Eastern Region of India

In collaboration with Institute of Advanced Study in Science and Technology (IASST), Guwahati, some plants used by tribals in north eastern India were tested for their ability to counter the hepatotoxic effect in a paracetamol-induced liver toxicity model. Aqueous and methanolic extracts of the plants Costos and Leucas lavandulaefolia were tested. Extracts of both plants have been shown to exert hepatoprotective effect as evidenced by a decrease in SGOT and SGPT enzyme activities and histopathologic examination.

In order to understand the underlying mechanism involved, the antioxidant potential of the extracts of the above plants and those of Cajanus cajan, Glycosmis and Sida rex were tested using in vivo linoleic oxidation assay. Many plant extracts exhibited significant antioxidant potential as demonstrated by a reduction in lipid peroxide levels in the in vivo assay. The hepatoprotective properties of the extracts of the plants studied may probably be related to their antioxidant properties.

Drug Metabolism in Obese Rats

Since excess body fat is known to be associated with increased risk of cancer, it was thought that obese rat model developed at the NIN could be a suitable model for fat-cancer studies. Before undertaking such investigations, the levels of drug metabolising enzymes, namely benzo(a) pyrene hydroxylase, microsomal epoxide hydrolase (phase I), uridine diphospho-glucuronyl transferase (UDPGT) and glutathione-s-transferase (GST) (phase II) were estimated in homozygous obese, heterozygous obese and lean rats. The activities of conjugating enzymes GST and UDPGT, which play an important role in detoxifying the xenobiotics, were significantly low in the homo and heterozygous obese rats as compared to lean control, thereby suggesting that the elimination of ingested xenobiotics may be impaired in such animals. These results suggest that obese rat model could be useful in studying xenobiotic metabolism.

OTHER STUDIES

Studies on Obese Mutant Rats

At the National Centre for Laboratory Animal Sciences (NCLAS), Hyderabad research activities realted to obese rats continued. These studies have shown that leptin gene amplification was highest for obese rats as compared to lean and carrier animals. However, nucleotide sequencing of leptin gene isolated from obese animals did not show any change/aberration indicating that the mutation in these animals is not with respect to leptin. The melanocortin receptor (MCR-4) expression in obese rat was found to be low as compared to lean and carrier animals. The random primer OPB15 was able to distinguish WNIN/Ob rats from WNIN stock rats as indicated by PCR based DNA fingerprint. The obese mutant stock (including lean, carrier and obese) as a whole was found to be at a greater risk of oxidative damage compared to parental WNIN rat stock, as shown by high levels of protein carbonyls and malic dehydrogenase. Correspondingly, the GSH levels were found to be significantly low in these animals. Amongst the tissues studied, the brain showed consistent ageing pattern with respect to all parameters. The opioid receptor levels (Delta, Kappa, Mu) were significantly reduced in obese animals compared to WNIN control. Binding studies showed lack of leptin receptors in obese animals.

Preliminary studies on spices revealed the hypoglycaemic effect of curry leaves and hypolipidaemic effect of turmeric in WNIN/GR-Ob rats.

 

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