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Biomedical subjects

W P James

Publications and source records attributed to W P James.

At least 19 recordsLinked to original sources
PubMed2000

One-year treatment of obesity: a randomized, double-blind, placebo-controlled, multicentre study of orlistat, a gastrointestinal lipase inhibitor.

OBJECTIVE: To assess the efficacy and tolerability of orlistat (Xenical) in producing and maintaining weight loss over a 12-month period. DESIGN: Patients were randomized to double-blind treatment with either orlistat 120 mg or placebo three times daily, in conjunction with a low-energy diet, for 12 months. SETTING: Five centres in the UK. SUBJECTS: 228 obese adult patients with body mass index between 30 and 43 kg/m2 and mean weight 97 kg (range 74-144 kg). INTERVENTIONS: All patients were prescribed a low-energy diet, providing 30% of energy from fat, designed to produce an individually tailored energy deficit of approximately 600 kcal/day, for a run-in period of 4 weeks and then 12 months, plus orlistat 120 mg or placebo three times daily. MAIN OUTCOME MEASURES: Change in body weight (the primary efficacy parameter), waist circumference and adverse events were reviewed regularly, together with serum lipids, insulin, glucose and plasma levels of fat-soluble vitamins and beta carotene. RESULTS: Based on an intent-to-treat analysis, after 1 y of treatment patients receiving orlistat had lost an average of 8.5% of their initial body weight compared with 5.4% for placebo-treated patients; 35% of the orlistat group lost at least 5% of body weight compared with 21% of the placebo group (P < 0.05), and 28% and 17%, respectively (P = 0.04) lost at least 10% of body weight. Orlistat-treated patients showed significant decreases (P < 0.05) in serum levels of total cholesterol, low density lipoprotein cholesterol, and in the low density lipoprotein: high density lipoprotein ratio in comparison with placebo. Both groups had similar adverse-event profiles, except for gastrointestinal events, which were 26% more frequent in the orlistat group but were mostly mild and transient. To maintain normal plasma levels of fat-soluble vitamins, supplements of vitamins A, D and E were given to 1.8%, 8.0% and 3.6%, respectively, of orlistat-treated patients, compared with 0.9% of placebo-treated patients for each vitamin type. After 1 y, the decrease in vitamin E and beta carotene was significantly greater in orlistat-treated patients compared with those receiving placebo (P < 0.001). No significant change was found in the mean vitamin E:total cholesterol ratio in either group after 52 weeks. CONCLUSIONS: Orlistat, in conjunction with a low-energy diet, produced greater and more frequent significant weight loss than placebo during 1 y of treatment. One-third of orlistat-treated patients achieved clinically relevant weight loss (> or = 5% initial body weight). There was also an improvement in relevant serum lipid parameters. Fat-soluble vitamin supplements may be required during chronic therapy. Orlistat was well tolerated and offers a promising new approach to the long-term management of obesity.

Adult↗
PubMed1999

New understanding in obesity research.

A public-health approach considers the relevance of nutritional research in the prevention and management of obesity. Well-defined and internationally-agreed definitions based on BMI allow an assessment of the worldwide prevalence of overweight and obesity. There are about 250 million obese adults in the world, and many more overweight. Obesity is emerging in the Third World, first in urban middle-aged women. With economic developments, obesity then occurs in men and younger women. In the West childhood obesity is rapidly emerging, with concern that early-onset obesity is especially hazardous. In Asians the risks of excess visceral fat occur at lower body weights than in Caucasians. The propensity to visceral obesity in Asians may relate to malnourished mothers and low birth weight. The International Obesity Task Force is considering many issues, including the health economics of obesity. It has developed a strategy to define childhood obesity, which in children over 6 years is likely to predict long-term weight and health problems. While the search for genetic markers of obesity continues, with particular interest in the leptin gene, it is clear that societal change, with the decline in physical activity and the passive overconsumption of high-fat diets are major contributors to the global increase in obesity. The public-health aspects of obesity research are therefore challenging.

Asia↗
PubMed1999

The potential use of maternal size in priority setting when combating childhood malnutrition.

OBJECTIVE: To devise a strategy for assessing the nutritional status of a household and specifying the major needs in combating childhood wasting, distinguishing between inadequate food availability, poor parental care and/or the need for improved public health measures. DESIGN: An evaluation of the relationship between children's wasting, stunting, or underweight and mothers' or adult women's body mass indexes (BMIs) in the same household. A household was designated as 'malnourished' on the basis of a single child's weight/height of < -2.0 s.d. or at risk of being malnourished if the Z-score was below--1.5. Adult women's BMI was taken to signify adequate household food availability. Sibling concordance of anthropometric measures was investigated. RESULTS: A wide variety of prevalence of severe (BMI < 16.0), moderate (BMI 16.0-16.9) and marginal (17.0-18.4) malnutrition existed in the various study areas. The worst condition was recorded in India, while 18% of the women in Zimbabwe were classified as obese. Similarly wide variation in the prevalence of child wasting and stunting was observed, with the Indian children again faring worst and those in Zimbabwe the best. The within-household analysis of concordance gave higher concordance for height than for weight between siblings. Mothers' BMI was highly correlated with the BMI of all other adult women in the same household and the BMI of all the women was found to be as useful as that of the mother for relating to children's anthropometry. Households with mothers of normal body weight but wasted children were designated as in need of public health measures and improved parental care rather than of enhanced food security. The distribution of households on this combined basis of maternal BMI and child nutritional status highlighted very diverse situations in the various study areas, with higher proportions of combined maternal and child malnutrition in India and in some areas of Ethiopia, while in Zimbabwe only 1-2% presented this condition. On this basis, the principal problem in India was food security; in Zimbabwe household security was rarely apparent, so public health measures and maternal care were designated as problems. In three Ethiopian communities there was a mixture of needs. CONCLUSIONS: A relatively simple household-based approach is proposed to discriminate the most pressing needs in combating childhood malnutrition, and a policy-making tool is suggested for setting priorities in community action.

Adolescent↗
PubMed1999

Report of the IDECG Working Group on the modulating effect of stressors on the upper and lower limits of lipid and carbohydrate intake. International Dietary Energy Consultative Group.

The recommended caloric intake should be increased by 2870kJ (670Kcal)/d in the exclusively breast-feeding woman. Of this increase, 10% should be ingested as protein, up to 50% as lipid and no less than 40% as carbohydrate. If weight loss is desired lipid intake can be reduced but carbohydrate intake should be maintained. Of the total energy increment 3% should be supplied by essential fatty acids (linoleic and alpha-linolenic acids) and 0.5% by n-3 fatty acids. The issue of dietary supplementation with long-chain polyunsaturated fatty acids remains for future research.

Dietary Carbohydrates↗
PubMed1998

What are the health risks? The medical consequences of obesity and its health risks.

It is important to establish what the medical view of obesity should be. An important step is the development of a standardised definition of obesity. The World Health Organisation (WHO) has proposed body mass index (BMI) as a simple measure of obesity. Whereas BMI has great clinical utility, it should be remembered that calculation of a raised BMI does not automatically indicate a high degree of adiposity. This is because BMI does not distinguish between weight due to excess fat, and weight due to a large mass of muscle or bone. Gender and age also have to be considered when evaluating BMI measurements. Obesity is related to many disorders, most of which are metabolic in origin. For example, hypertension and the adverse lipid profile associated with obesity increases the risk of coronary heart disease (CHD). There is also a profound association between obesity, particularly intra-abdominal adiposity, and the development of non-insulin dependent diabetes mellitus (NIDDM). Obesity has reached epidemic proportions. This is paralleled by an increasing incidence of NIDDM. There is no doubt that weight gain and obesity are major clinical problems, which need to be prevented and managed more effectively. This is essential, given the role of obesity in many of the chronic health problems affecting westernised societies.

Adult↗
PubMed1997

Socioeconomic determinants of health. The contribution of nutrition to inequalities in health.

Social class differences in health are seen at all ages, with lower socioeconomic groups having greater incidence of premature and low birthweight babies, heart disease, stroke, and some cancers in adults. Risk factors including lack of breast feeding, smoking, physical inactivity, obesity, hypertension, and poor diet are clustered in the lower socioeconomic groups. The diet of the lower socioeconomic groups provides cheap energy from foods such as meat products, full cream milk, fats, sugars, preserves, potatoes, and cereals but has little intake of vegetables, fruit, and wholewheat bread. This type of diet is lower in essential nutrients such as calcium, iron, magnesium, folate, and vitamin C than that of the higher socioeconomic groups. New nutritional knowledge on the protective role of antioxidants and other dietary factors suggests that there is scope for enormous health gain if a diet rich in vegetables, fruit, unrefined cereal, fish, and small quantities of quality vegetable oils could be more accessible to poor people.

Adult↗
PubMed1997

Carbohydrates and energy balance.

In the early 1970s carbohydrates (CHOs) were believed to induce overconsumption and excess fat deposition. They are now perceived to protect against these consequences. This paper evaluates the evidence for this change of interpretation by considering (1) the energy content of CHOs, (2) the energetic efficiency with which they are handled by the body, and (3) their effects on appetite, relative to other macronutrients. CHOs are the least energy-dense macronutrients (delta Hc) and exhibit the greatest variability in digestibility. Doubling the usual levels of nonstarch polysaccharides (fiber) may decrease digestibility of a Western diet by 5%. De novo lipogenesis from dietary CHO is energetically inefficient but very limited on Western diets, which are relatively high in fat. There appears to be a hierarchy (protein > CHO > fat) in the extent to which the stores of the macronutrients are autoregulated by oxidation. Excess CHO intake tends to promote storage (but not de novo synthesis) of fat. The thermogenic effects of CHO are therefore relatively limited on Western diets. Per MJ of energy ingested, macronutrients differentially affect satiety (protein > CHO > fat) under conditions where fat is disproportionately energy dense. Isoenergetically dense loads of fat and CHO exert less pronounced differences on satiety. Under some conditions HC diets promote excess energy intakes. There is little evidence that a CHO-rich diet, or one with intense sweeteners, promotes spontaneous weight loss.

Dietary Carbohydrates↗
PubMed1997

High D-glucose does not affect binding of alpha-tocopherol to human erythrocytes.

The role of alpha-tocopherol uptake system in human erythrocyte in the uptake of plasma alpha-tocopherol has been suggested. However no information is available on alpha-tocopherol uptake activity of human erythrocytes in the presence of high levels of D-glucose which is known to lead to pathological alterations in different cells including human erythrocytes. Therefore, in order to examine the effect of D-glucose on the binding of alpha-tocopherol to human erythrocytes, the binding characteristics of alpha-tocopherol to these cells were established first. Binding of [3H]alpha-tocopherol to human erythrocytes was both saturable and specific. Scatchard analysis of alpha-tocopherol binding to these cells showed the presence of two independent classes of binding sites with widely different affinities. The high affinity binding sites had a dissociation constant (Kd1) of 90 nM with a binding capacity (n1) of 900 sites per cell, whereas the low affinity binding sites had a dissociation constant (Kd2) of 5.2 microM and a binding capacity (n2) of 105,400 sites per cell. Trypsin treatment abolished all the alpha-tocopherol binding activity. Competition for the binding of alpha-tocopherol to human erythrocytes was effective with other homologues of alpha-tocopherol (beta-tocopherol, gamma-tocopherol and delta-tocopherol) and their potency was almost equal to alpha-tocopherol itself. The order of preference was alpha-tocopherol > beta-tocopherol > or = gamma-tocopherol > or = delta-tocopherol. Incubation of human erythrocytes with various concentrations of D-glucose did not affect alpha-tocopherol uptake activity. Our data demonstrate the presence of an alpha-tocopherol uptake system in human erythrocytes and that the alpha-tocopherol uptake activity is not modulated by the presence of D-glucose.

Binding Sites↗
PubMed1997

A new look at dietary carbohydrate: chemistry, physiology and health. Paris Carbohydrate Group.

The current view of dietary carbohydrates as simply providing us with energy is outdated. Because of their varied chemistry and physical form the rate and extent to which the different types are digested in and absorbed from the small intestine varies. This in turn leads to affects on satiety, blood glucose and insulin, protein glycosylation, lipids and bile acids. Some carbohydrates reach the colon where they are fermented and affect many aspects of large bowel function, colonocyte and hepatic metabolism. A new framework for classifying and measuring food carbohydrates is needed to allow a greater understanding of the role of individual species in health and to inform the public of their importance. A classification based primarily on molecular size (degree of polymerisation) into sugars, oligosaccharides and polysaccharides, is suggested, with sub-groups identified by the nature of the monosaccharides. Greater knowledge of the chemical and physical properties of carbohydrates allow a more precise relation with physiology and health to be drawn. The Carbohydrate Group met in Paris in December 1995 at the invitation of Gerard Pascal, Director of CNERNA. Financial support for the meeting was provided by CNERNA.

Carbohydrates↗
PubMed1997

alpha-Tocopherol binding activity of red blood cells in smokers.

Despite high plasma levels of vitamin E, red blood cell membranes contain relatively low levels of vitamin E. This suggests the existence of a selective vitamin E uptake/regeneration system in human red blood cell membranes. alpha-Tocopherol binding sites on human red blood cells are thought to be involved in the uptake of alpha-tocopherol from the plasma. To understand the role of the uptake system we have compared the alpha-tocopherol content and binding activity of red blood cells from smokers and non-smokers. The specific binding of [3H] alpha-tocopherol to pure red blood cell preparations from smokers (n = 7, 28.4 +/- 2.8 years) was 30.6 +/- 3.2 fmoles per 3 x 10(8) red blood cells and for non-smokers (n = 17, 27.9 +/- 1.3 years) was 41.7 +/- 3.7 fmoles per 3 x 10(8) red blood cells. Thus alpha-tocopherol uptake activity was significantly lower in smokers (P = 0.05). Red blood cells from smokers contained less (1.8 +/- 0.4 micrograms/gHb) alpha-tocopherol than non-smokers (2.8 +/- 0.3 micrograms/gHb), (P < 0.05), despite plasma levels of alpha-tocopherol being similar: 12.9 +/- 0.8 microM in non-smokers vs. 12.7 +/- 0.5 microM in smokers. However, adjusting plasma alpha-tocopherol for total plasma cholesterol plus triacylglycerols showed alpha-tocopherol levels were higher (P < 0.01) in non-smokers (2.84 +/- 0.10 mumol alpha-tocopherol/ mmol [cholesterol+triacylglycerol]) than in smokers (2.36 +/- 0.11 mumol alpha-tocopherol/mmol [cholesterol+triacylglycerol]). The reduced alpha-tocopherol levels in red blood cells from smokers may be due to impairment of alpha-tocopherol uptake activity. The reduced levels of alpha-tocopherol in smokers red blood cells was not associated with any changes in cell membrane fluidity. At present it is not known whether supplementation of smokers with vitamin E would normalise the alpha-tocopherol uptake activity of red blood cells.

Adult↗
PubMed1997

A one-year trial to assess the value of orlistat in the management of obesity.

OBJECTIVES: This paper describes the methodology of a multicentre study designed to assess the efficacy and tolerability of orlistat 120 mg tid as therapy for inducing weight loss in excess of that achieved with a moderately calorie-restricted diet alone. The results from a single centre are presented to illustrate the nature of the response. DESIGN: This was a double-blind, randomized, parallel-group, placebo-controlled multicentre study. A four-week, single-blind, placebo run-in period preceded a 52 week double-blind treatment period during which patients received either orlistat or placebo three times a day. At the start of the run-in period, all patients were placed on a diet containing approximately 30% of calories as fat and designed to cause an energy deficit of approximately 600 kcal/d. SUBJECTS: Patients of either sex, more than 18 y of age, with a body mass index (BMI) between 30 and 43 kg/m2 were eligible for enrolment. MEASUREMENTS: Efficacy assessments included: measurements of body weight; anthropometry; quality of life; blood pressure; serum lipids; fasting serum glucose and insulin. Safety assessments included: adverse events; vital signs; ECG; renal and gallbladder ultrasound; haematology; serum biochemistry. OUTCOME: In the single centre there was a reduction in body weight of 5.5 +/- 4.5 (s.d.) kg (5.7% reduction) in the placebo group and 8.6 +/- 5.4kg in the orlistat-treated group (8.4% reduction) by six months. Thereafter, the placebo group tended to relapse whereas the orlistat group maintained their loss (2.6% vs 8.4% reduction from initial value at 52 weeks). Total and LDL cholesterol fell by 0.05 mmol/l (1.6%) and 0.14 mmol/l (4.2%), respectively, in orlistat treated patients. The drop-out rate was 48% in the placebo group and 39% in the orlistat group. Intestinal symptoms related to orlistat were significantly increased compared to placebo but were well tolerated. Fat soluble vitamin levels remained within the normal range in the treatment group; the reduction seen in alpha-tocopherol levels in patients receiving orlistat was normalized by the decrease in plasma cholesterol concentrations. Beta-carotene and vitamin D concentrations also decreased in orlistat-treated patients. CONCLUSIONS: This preliminary analysis suggests that orlistat, when used with a health-promoting low-fat and moderately energy-restricted diet, confers advantages in the long-term management of obesity.

Adult↗
PubMed1997

The starch and total sugar content of Mexican fruit and vegetables.

The starch and total sugar contents of 20 types of fruit, 28 types of vegetables and six different herbs, grown in Mexico, were analysed. The selection was based on dietary surveys to identify those foods most widely consumed. Starch was determined by an enzymatic method whilst total sugar was determined gravimetrically. The foods were grouped according to the Southgate classification. Fruits contained little starch (range 0-4 g/100 g fresh weight (FW) except in the case of the plantain (31 g/100 g FW starch), whereas vegetables showed a higher concentration with tubers in the range 10-20 g/100 g FW starch. Legumes contained 0-5 g/100 g FW; amongst the capsicum group the chilli poblano had the highest concentration at 1.3 g/100 g FW starch. The concentration of sugars in fruits ranged from 0.6 g/100 g FW to 21.1 g/100 g FW.

Carbohydrates↗
PubMed1996

The epidemiology of obesity.

An agreed definition of obesity as a body mass index (BMI) of 30 kg/m2 or more seems to be accepted everywhere except in North America. Recent data confirm the importance of setting an upper individual BMI limit of 25 kg/m2 and a population optimum of 20-23 kg/m2. Some adjustment of BMI should be made in individuals and populations with disproportionate shapes, e.g. short or long legs, and morbidity and mortality risks are especially important in those with a waist measurement of about 102 cm or more, the risk increasing from 88 cm. Waist measurements should probably now be substituted for the waist/hip circumference ratio. Diabetes is universally closely linked to increases in BMI, and cardiovascular disease is amplified by obesity, particularly in western societies where other dietary factors contribute substantially. Industrialization with reduced physical activity and higher fat diets lead to obesity first in middle-aged women, then in men, with younger adults and children eventually being affected. Physiological studies display the interaction of physical activity and energy dense, high fat diets and explain the secular, age- and social class-related trends throughout the world. Intergenerational amplification of obesity may be underway, so the public health implications of obesity are immense.

Adult↗