Nature's bountiful gift to humankind: Vegetables & fruits & their role in cardiovascular disease & diabetes

Fruits and vegetables (FVs) are recognized as healthy constituents of diet and a sustainable solution to the existing twin burden of micronutrient deficiencies and non-communicable diseases in developing and developed countries. In general, FVs are nutrient dense foods low in energy, containing varying amounts of vitamins and minerals including carotenoids, B vitamins, vitamin C, iron, zinc, potassium, calcium, magnesium and fibre. These are abundantly rich in phytochemicals that function as antioxidants, anti-atherosclerotic and anti-inflammatory agents. This review summarizes some epidemiological, prospective cohort and intervention studies on the health benefits of FVs in relation to cardiovascular disease, obesity and diabetes. The rich varieties of FVs available, their composition, production scenario in India, dietary intake and trends over time, barriers to sufficient intake mainly sociocultural, economic and horticulture environment, policies for promotion and prevention of diseases are considered.

Biological activities of Sarcanthus pauciflorus.

Sarcanthus pauciflorus is a pendulous epiphytic orchid belonging to the family Orchidaceae. The present study was conducted to determine antimicrobial, antioxidant, anthelmintic and insecticidal efficacy of methanol extract of S. pauciflorus. Antimicrobial activity of methanol extract was determined against four bacteria and two fungi by Agar well diffusion method. Antioxidant activity was performed by DPPH free radical scavenging and Ferric reducing assay. Anthelmintic activity was studied on the basis of time taken for paralysis and death of adult Indian earthworms by the extract. Insecticidal activity, in terms of larvicidal effect, was evaluated using II instar larvae of Aedes aegypti. Total phenolic content of extract was estimated by Folin-Ciocalteau reagent assay. Phytoconstituents viz., tannins, saponins and glycosides were detected in methanol extract. Content of total phenolics was found to be 258.65 mg GAE/g of extract. All test bacteria and fungi were susceptible to extract of orchid. Bacillus subtilis and Cryptococcus neoformans were susceptible to high extent among bacteria and fungi respectively. Gram positive bacteria have shown greater susceptibility than Gram negative bacteria to extract. The extract exhibited marked dose dependent scavenging of DPPH free radicals. An increase in absorbance at 700nm revealed reducing power of the extract. The extract caused paralysis and death of adult Indian earthworms in a dose dependent manner. The lethal effect of extract on II instar larvae of Aedes aegypti was found to be dose dependent. The results of the present study shows that the methanol extract of S. pauciflorus is found to possess antimicrobial, antioxidant, anthelmintic and insecticidal activities which might be attributed to the presence of secondary metabolites. Further experimentations concerned with isolation of the bioactive components present in the orchid and determination of their biological activities are under progress.

Fibrinogen and homocysteine levels in coronary artery disease.

Conventional risk factors like high serum cholesterol, smoking and hypertension do not explain all the mortality and morbidity due to coronary artery disease in Indian population. Novel factors like plasma fibrinogen and homocysteine have been currently recognised as independent risk factors for coronary artery disease. A case-control study was carried out to examine the role of plasma fibrinogen, homocysteine, lipid profile and anthropometric parameters in angiographically established coronary artery disease patients. The relationship between the biochemical and anthropometric parameters was also examined. Fifty-eight male patients in the age range of 35-60 years with angiographically established coronary artery disease and equal number of matched-controls were the subjects of this study. Cases with coronary artery disease had significantly higher waist-to-hip ratio, waist-to-thigh ratio, plasma fibrinogen and total cholesterol. Mean plasma total homocysteine levels were not significantly different between cases and controls. In Indian population, elevated plasma fibrinogen and abdominal obesity appear to be significantly associated with coronary artery disease.

Bioactive phytochemicals with emphasis on dietary practices.

Diet can modify the pathophysiological processes of various metabolic disorders and can be an effective preventive strategy for various disease processes most of which are known to involve oxidative damage. Both nutrient and non-nutrient components of the diet have been recognized for their anti-oxidant and other potential benefits. Plant foods contain phytochemicals such as flavonoids, phenolic acids, etc., which show biological activity. Some common foods used in Indian culinary practices were assessed for their anti-oxidant, anti-mutagenic and anti-carcinogenic effects and vitamin D activity and evaluated for their plausible biological effects. Green leafy vegetables had the highest anti-oxidant activity followed by wheat and rice. Cooking decreased this activity. Eugenol, the active principle of clove, was shown to offer protection against CCl4 induced hepatotoxicity in rats. It also showed anti-peroxidative activity in addition to decrease in O2 formation. Studies on the anti-carcinogenic effect of turmeric/curcumin revealed that both are potent anti-mutagens in vivo and reduce the adducted DNA levels in liver of rates challenged with B(a)P. In another study, Syrian hamsters receiving turmeric/curcumin through diet or local paint on cheek pouch had lower tumour burden as well as adducted DNA level against 7-12-DMBA challenge. Turmeric/curcumin were found to be better anti-tumour agents when given in the post initiation phase of carcinogenesis. The beneficial effect of turmeric was found to be due to its anti-oxidant potential. Studies on humans at risk of palatal cancer due to reverse smoking showed that turmeric (1 g/day) for 9 months had a significant impact on the regression of precancerous lesions. Onion and garlic also possess anti-mutagenic principle. Further studies on the bioactive phytochemicals in plants showed that certain plants belonging to Solanaceae (Cestrum diurnum, Lycopersicon esculentum and Solanum melongena) have calcinogenic potential and vitamin D like activity. In view of the vast data on bioactive principles from plants, it is suggested that dietary prevention coupled with other life-style changes in perhaps the right answer for prevention of cancer and other chronic diseases in India.

Impact evaluation of iron & iodine fortified salt.

As a novel approach to tackle the problems of iron deficiency anaemia and iodine deficiency disorders (IDDs), which often coexist, the National Institute of Nutrition has developed iron and iodine fortified common salt (double fortified salt-DFS) as a public health measure. This salt has undergone a battery of laboratory and field tests to evaluate its feasibility for use in a national programme. The DFS is designed to provide 1 mg of iron and 15 micrograms of iodine per gram of common salt. This was made possible by the inclusion of a polyphosphate stabilizer, sodium hexametaphosphate (SHMP) at 1 per cent level. The stability of iron and iodine was found to be good up to 6 months. However, the stability of iodine depended upon the quality of the salt used for fortification. The biological effects of long-term consumption of DFS were evaluated in experimental rats and in field trials. Both iron and iodine from the salt were found to be biologically available in regenerating haemoglobin and in increasing excretion of iodine in urine. When this salt was tested in tribal villages endemic for goitre and iron deficiency anaemia, the bioresponse was good with regard to the iodine status but was not uniform in all segments with regard to iron, probably due to confounding variables. In a study carried out in residential school children where such variables did not exist, DFS was found to have significant impact on haemoglobin status in anaemic children and improved their urinary iodine excretion. The consumption of DFS for 2 yr did not have any adverse effects in school children as well as in the tribal population. Parameters related to calcium homeostasis were not altered in children receiving DFS. Histopathological examination of tissues and radiological examination of bone did not reveal any abnormality in DFS fed rats. Similarly serum and urinary parameters related to calcium and phosphorus were not altered in DFS fed rats. Therefore, DFS is presented as a feasible and effective strategy to control the double deficiency of iron and iodine in our community.

Diet, nutrition & cancer--the Indian scenario.

Cancer continues to be a major health problem despite advances in medical technology for its diagnosis and treatment. Hence prevention strategies are needed to decrease the burden of the disease. Of all the environmental factors, dietary components appear to play an important role in the initiation/progression of the disease. Nutrients and non-nutrients in the diet can influence the carcinogenic process at various stages, from initiation to overt manifestation. The National Institute of Nutrition has conducted studies on several aspects of diet-cancer inter-relationships. These include studies on metabolic susceptibility, case-control approach to determine the risk factors and intervention studies to determine the role of nutrients and non-nutrient components on preneoplastic events. Extensive work has been carried out demonstrating the antimutagenic/anticarcinogenic potential of some commonly consumed spices and vegetables such as turmeric, mustard, green leafy and allium species of vegetables. Dietary intervention for cancer prevention is needed to control the disease besides avoiding risk factors such as smoking and alcoholism and exposure to genotoxicants. Public education and awareness about the beneficial effects of consuming a healthy diet including plenty of fresh vegetables and fruits with spices such as turmeric in adequate amounts to prevent cancer are required.

N-nitrosamines in Indian beers.

Presence of volatile N-nitrosamines in beer and other alcoholic drinks are well documented in developed countries. Analysis of 120 beer samples of various brands/batches showed positivity for N-nitrosodimethylamine (NDMA) in more than 100 samples. The overall mean of 3.6 ppb of NDMA is higher than those currently found in Western countries. Since N-nitrosamines are proven carcinogens in animals at several sites it is necessary to keep their levels of exposure to as low as possible.

A case control study of selenium in cancer.

As selenium has been shown to be a risk modifier of cancer at several sites in a case-control approach, selenium nutriture was studied in oral and oesophageal cancer patients. The mean selenium level in oral cancer patients was 102.6 ng/ml and in oesophageal cancer 103.3 ng/ml, while in the matched controls it was 117.5 and 116.2 ng/ml respectively. Relative risk estimates were 3.16 (P < 0.02) and 16.0 (P < 0.01) in oral and oesophageal cancer patients respectively. The risk appears to increase with selenium levels lower than 115 ng/ml.

Basic concepts of clinical pharmacokinetics.

Clinical pharmacology is now a well established discipline. Unlike the yester years when dosage schedules were determined by trial and error, in the present day selection of dose, dosage interval and route of administration are based on pharmacokinetic and pharmacodynamic principles. The primary utility of pharmacokinetics is to study the process of absorption, distribution, metabolism and elimination of drugs, fundamental for drug action. Individuals show a wide variation in kinetic parameters due to internal and external factors. Sometimes change in one variable may be compensated by change in another variable so that dose need not be altered e.g. metabolism of some drugs is increased in thyrotoxicosis but due to increased protein binding overall dose adjustment may not be required. On the other hand sometimes variations in these parameters can markedly affect the plasma concentrations of and the pharmacological response to drugs e.g. anticonvulsant treatment in oral contraceptive users, phenylbutazone addition in warfarin therapy. Drug concentrations can be measured in plasma, urine or saliva. Equipped with this knowledge the modern physician will be able to make a wiser use of drugs under altered physiological conditions like pregnancy, lactation, infancy, old age and pathological states like renal and liver failure and shock.