Osteoarthritis, obesity and weight loss: evidence, hypotheses and horizons - a scoping review.

Obesity is widely acknowledged as a risk factor for both the incidence and progression of osteoarthritis, and has a negative influence on outcomes. Loss of at least 10% of body weight, coupled with exercise, is recognized as a cornerstone in the management of obese patients with osteoarthritis, and can lead to significant improvement in symptoms, pain relief, physical function and health-related quality of life. However, questions still remain surrounding optimal management. Given the significant health, social and economic burden of osteoarthritis, especially in obese patients, it is imperative to advance our knowledge of osteoarthritis and obesity, and apply this to improving care and outcomes. This paper overviews what is already known about osteoarthritis and obesity, discusses current key challenges and ongoing hypotheses arising from research in these areas, and finally, postulates what the future may hold in terms of new horizons for obese patients with osteoarthritis.

Formula food-reducing diets:A new evidence-based addition to the weight management tool box.

The changing pattern of obesity-related disease has created a need for a greater range of weight management options for the increasing number of people for whom weight loss and maintenance cannot be addressed by conventional dietary methods. Formula diet weight loss programmes [very low-calorie diets (VLCDs) (400-800 kcal/day) and low-calorie diets (LCDs) (800-1200 kcal/day)] can deliver weight loss at rates of 1-2 kg/week. This rate of weight loss can result in 10-20 kg weight loss in 8-12 weeks. Many health benefits associated with weight reduction seem to require between 10 and 20 kg weight loss. Formula diet programmes can result in weight loss, reduction of liver volume and reduction of visceral fat before bariatric surgery; weight loss before knee joint replacement surgery has also been shown. The benefit of pre-operative weight loss is still under investigation and such practices before bariatric surgery are variable in surgical units across the UK. Weight loss with formula diet in obesity-associated conditions where inflammation is an important component, such as osteoarthritis and psoriasis, has been demonstrated. Maintenance of about 10% of initial bodyweight loss, with symptom improvement in elderly obese people with knee osteoarthritis, has been shown over a period of 4 years. In obese people with psoriasis, weight loss with skin improvement has been maintained for 1 year. Clinical trials are currently underway to examine the merits of an initial weight loss with formula diet in pre-diabetes, in early type 2 diabetes and in insulin-treated type 2 diabetes. Rapid initial weight loss can result in rapid symptom improvement, such as reduced joint pain in osteoarthritis, improved sleep quality in obstructive sleep apnoea, reduced shortness of breath on exertion, reduced peripheral oedema and rapid improvement in metabolic control in diabetes, all changes that are highly motivating and conducive towards compliance. There is also some evidence for improved vitamin D status and maintained bone health in elderly obese people with osteoarthritis but more research is needed. Rapid initial weight loss was feared to be followed by rapid weight regain. However, provided initial weight loss is delivered in parallel with an intense education programme about nutrition, cooking, shopping and lifestyle for long-term maintenance; and where long-term support is provided, subsequent weight maintenance after VLCDs and LCDs has been shown to be possible. A recent literature review identified high-protein diets, obesity drugs and partial use of formula meal replacements as methods which can result in statistically significantly greater weight maintenance after initial weight loss with VLCDs or LCDs. Anxiety about serious adverse side effects seems to be unfounded although users need to be aware of both minor and more serious, though very infrequent, adverse events, such as gallstones and gallbladder disease.

Improved nutritional status and bone health after diet-induced weight loss in sedentary osteoarthritis patients: a prospective cohort study.

BACKGROUND/OBJECTIVES: Obese subjects are commonly deficient in several micronutrients. Weight loss, although beneficial, may also lead to adverse changes in micronutrient status and body composition. The objective of the study is to assess changes in micronutrient status and body composition in obese individuals after a dietary weight loss program. SUBJECTS/METHODS: As part of a dietary weight loss trial, enrolling 192 obese patients (body mass index >30 kg/m2) with knee osteoarthritis (>50 years of age), vitamin D, ferritin, vitamin B12 and body composition were measured at baseline and after 16 weeks. All followed an 8-week formula weight-loss diet 415-810 kcal per day, followed by 8 weeks on a hypo-energetic 1200 kcal per day diet with a combination of normal food and formula products. Statistical analyses were based on paired samples in the completer population. RESULTS: A total of 175 patients (142 women), 91%, completed the 16-week program and had a body weight loss of 14.0 kg (95% confidence interval: 13.3-14.7; P<0.0001), consisting of 1.8 kg (1.3-2.3; P<0.0001) lean body mass (LBM) and 11.0 kg (10.4-11.6; P<0.0001) fat mass. Bone mineral content (BMC) did not change (-13.5 g; P=0.18), whereas bone mineral density (BMD) increased by 0.004 g/cm2 (0.001-0.008 g/cm2; P=0.025). Plasma vitamin D and B(12) increased by 15.3 nmol/l (13.2-17.3; P<0.0001) and 43.7 pmol/l (32.1-55.4; P<0.0001), respectively. There was no change in plasma ferritin. CONCLUSIONS: This intensive program with formula diet resulted in increased BMD and improved vitamin D and B12 levels. Ferritin and BMC were unchanged and loss of LBM was only 13% of the total weight loss. This observational evidence supports use of formula diet-induced weight loss therapy in obese osteoarthritis patients.

Development and validation of a structured questionnaire for the diagnosis of oral allergy syndrome in subjects with seasonal allergic rhinitis during the UK birch pollen season.

BACKGROUND: Birch pollen-associated oral allergy syndrome, also known as pollen-food syndrome (PFS), is the most common food allergy in adults in the United Kingdom. Because of its characteristic rapid onset of oro-pharyngeal symptoms associated with specific plant foods, it was hypothesized that a history-based questionnaire could accurately diagnose PFS in subjects with rhino-conjunctivitis symptoms in the UK springtime. OBJECTIVE: In this study of diagnostic accuracy, we aimed to validate a simple PFS diagnostic questionnaire and algorithm against a reference diagnostic test method (RTM) comprising diagnosis by expert evaluation of clinical history, skin prick tests and oral food challenge, in subjects reporting allergic rhinitis (AR) in the UK birch pollen season from March to May. METHODS: Participants were UK adults reporting symptoms of spring time-AR (hayfever). They self-completed a diagnostic questionnaire in addition to undergoing an RTM comprising clinical history, skin prick testing to foods and pollens and oral food challenge. Subjects who reported anaphylaxis were excluded on the basis that they required specialist referral. RESULTS: One hundred and twenty three subjects took part in the study. Data from 110 participants were analysed; of the 13 exclusions, four provided insufficient data and nine reported anaphylaxis such that they warranted specialist assessment. Fifty-two participants (47%) were diagnosed with PFS by the RTM in comparison with 51 (46%) by a diagnostic questionnaire and algorithm (P=1.000, McNemar's test). The diagnostic questionnaire and algorithm had a sensitivity of 0.90 (0.78-0.96), a specificity of 0.93 (0.82-0.97), a positive predictive value of 0.92 (0.80-0.97) and a negative predictive value of 0.91 (0.80-0.96) when measured against the RTM. CONCLUSION AND CLINICAL RELEVANCE: The diagnostic questionnaire and algorithm is a practical and robust tool, which enables rapid identification, and therefore management, of individuals with PFS who experience rhino-conjunctivitis symptoms in the UK birch pollen season. Registered with CinicalTrials.Gov. registration number NCT00854958.

A comprehensive review of oral glucosamine use and effects on glucose metabolism in normal and diabetic individuals.

Glucosamine (GlcN) is a widely utilized dietary supplement that is used to promote joint health. Reports that oral GlcN supplementation at usual doses adversely affects glucose metabolism in subjects with impaired glucose tolerance have raised concerns that GlcN should be contraindicated in individuals with diabetes and those at risk for developing it. This review addresses its potential, when used at typical doses, to affect glucose metabolism and insulin sensitivity in healthy individuals and those with diabetes or 'pre-diabetes'. Publicly available scientific information and data on GlcN were systematically compiled using the electronic search tool, Dialog , and reviewed with special emphasis on human studies. In long-term clinical trials, including those containing subjects with type 2 diabetes or 'pre-diabetes', GlcN produced a non-significant lowering of fasting blood glucose concentrations in all groups of subjects treated for periods of up to 3 years. Owing to limitations in study design, conclusions based on studies that report adverse affects of GlcN on insulin sensitivity and glucose tolerance in pre-diabetic subjects are suspect. However, no definitive long-term studies of GlcN use for individuals with pre-diabetes are available. Nevertheless, based on available evidence, we conclude that GlcN has no effect on fasting blood glucose levels, glucose metabolism, or insulin sensitivity at any oral dose level in healthy subjects, individuals with diabetes, or those with impaired glucose tolerance.

Comparison of a low-energy diet and a very low-energy diet in sedentary obese individuals: a pragmatic randomized controlled trial.

UNLABELLED: There is no consensus on whether 'very low-energy diets' (VLED; <800 kcal d(-1) ) cause greater weight loss in obese individuals than 'low-energy diets' (LED; 800-1200 kcal d(-1) ). The objective was to determine whether a very low-energy formula diet would cause greater weight loss than a formula 810 kcal d(-1) LED in older sedentary individuals. This is a pragmatic randomized controlled trial. INCLUSION CRITERIA: obesity (body mass index [BMI] > 30); age >50 years, with knee osteoarthritis. Participants were randomized to VLED (420-554 kcal d(-1) ) or LED (810 kcal d(-1) ) for 8 weeks, followed by a fixed-energy (1200 kcal d(-1) ) diet with food and two diet products daily for 8 weeks. In all, 192 participants were randomized. Mean age was 63 years (standard deviation: 6), mean weight 103.2 kg (15.0) and BMI of 37.3 kg m(-2) (4.8) at baseline. Mean weight losses in VLED and LED groups were 11.4 kg (standard error: 0.5) and 10.7 kg (0.5) at week 8 and 13.3 kg (0.7) and 12.2 kg (0.6) at week 16. Mean differences between groups were 0.76 kg (95% confidence interval: -0.59 to 2.10; P = 0.27) and 1.08 kg (-0.66 to 2.81; P = 0.22) at 8 and 16 weeks, respectively. Loss of lean body mass was 2.1 kg (0.2) and 1.2 kg (0.4) (17% and 11% of the weight lost, respectively) at week 16 in the VLED and LED group with a mean difference of 0.85 kg (0.01 to 1.69; P = 0.047). Significant adverse effects comparing VLED and LED, were bad breath: 34 (35%) vs. 21 (22%), intolerance to cold: 39 (41%) vs. 17 (18%) and flatulence: 43 (45%) vs. 28 (29%) for VLED and LED at 8 weeks (P < 0.05 in all cases). The VLED and LED regimens were equally successful in inducing weight loss. The significantly lower loss of lean tissue in the LED group together with more frequently reported side effects in the VLED group, favours the choice of low-energy diet (LED) for the treatment of obesity.

Comparing two low-energy diets for the treatment of knee osteoarthritis symptoms in obese patients: a pragmatic randomized clinical trial.

OBJECTIVES: To evaluate in a prospective, randomized clinical trial (RCT), symptom response among obese knee osteoarthritis (OA) patients following a feasible, intensive weight-loss program for 16 weeks. METHODS: Eligible patients were obese [body mass index (BMI)>30 kg/m(2)]; >50 years old, with primary knee OA. Participants were randomized to either a very-low-energy diet (VLED) or a low-energy diet (LED) (415 kcal/day and 810 kcal/day, respectively), using commercially available formula foods - only for the first 8 weeks, managed by dieticians. The 8 weeks were followed by an additional 8-week period of a hypo-energetic diet consisting of normal food plus meal replacements (1200 kcal/day). The primary endpoint was the number of patients responding according to the Outcome Measures in Rheumatology Clinical Trials and Osteoarthritis Research Society International (OMERACT-OARSI) responder criterion. The statistical analysis was based on a non-responder intention-to-treat (ITT) population (baseline observation carried forward). RESULTS: One hundred and ninety two patients (155 (80.7%) females) with a mean age 62.5 years [standard deviation (SD) 6.4; range 50-78 years]; average BMI 37.3 (SD 4.8) were included. At 16 weeks, similar proportions of the VLED and LED groups, 59 (61.5%), and 63 (65.6%) patients, respectively, met the OMERACT-OARSI responder criteria, with no statistical significant difference between the groups (P=0.55). Combining the groups the pooled estimate was 64% meeting the responder criteria [95% confidence interval (CI) 57%, 70%]. There was an overall reduction in pain, corresponding to an average pain reduction on the visual analogue scale (VAS) of 11.1 (95%CI 13.6, 8.5) in the combined groups. At week 16 weight loss in the combined groups was 12.8 kg (95%CI: 11.84-13.66; P<0.001). 71% lost > or =10% body weight in both diet groups, with a pooled estimate of 74% (95%CI: 68-80%). CONCLUSION: No clinically significant differences were found between the 415 kcal/day and 810 kcal/day diets. A 16-week formula-diet weight-loss program resulted in a fast and effective weight loss with very few adverse events resulting in a highly significant improvement in symptoms in overweight patients with knee OA.

The effect of a 12-week low glycaemic index diet on heart disease risk factors and 24 h glycaemic response in healthy middle-aged volunteers at risk of heart disease: a pilot study.

OBJECTIVE: To compare the effects of two energy-restricted healthy diets, one with a low GI and one with a high GI, on heart disease risk factors and weight loss in subjects at risk of heart disease. DESIGN: A 12-week randomized parallel study of low and high GI, healthy eating diets was carried out. SETTING: The study was carried out at the Hammersmith Hospital. SUBJECTS: Eighteen subjects were recruited by advertisement and randomized to one of the two diets. Fourteen completed the study but one was excluded from the final analysis. METHODS: At randomization, subjects were advised to follow the intervention diet for 12 weeks. Before randomization and on completion of the study, anthropometrics, fasting cholesterol and glucose blood tests and 24-h glucose measurements were taken using a continuous glucose monitoring system (CGMS). Statistical analysis was carried out using non-parametric tests. Median (IQR) are presented. RESULTS: A significantly different dietary GI was achieved in the low GI (median: 51.3 (IQR: 51.0-52.0) compared to the high GI (59.3 (59.2-64.0) (P=0.032) group. By week 12, both groups reduced their energy intake by: low GI group: (-)167 ((-)312-(-)123) kcal/day (P=0018) vs high GI group: (-)596 ((-)625-(-)516) (P=0.018) kcal/day, the difference between the groups being significant (P=0.010). However, only the low GI group lost weight ((-)4.0 ((-)4.4-(-)2.4) kg (P=0.018) whereas the high GI group did not significantly change in weight ((-)1.5 ((-)3.6-0.8) kg (P=0.463). By week 12, the low GI group also had a significantly lower 24-h area under the curve (AUC) (7556 (7315-8434) vs 8841 (8424-8846) mmol-h/l (P=0.045) and overnight AUC (2429 (2423-2714) vs 3000 (2805-3072) mmol-h/l (P=0.006) glucose as measured by CGMS. There were no differences in the other heart disease risk factors assessed. CONCLUSIONS: This pilot study provides some evidence that consuming a low GI diet in addition to weight loss and healthy eating may reduce cardiovascular risk. Other potential benefits of GI might have been masked by weight loss in the low GI group. Larger-scale studies need to follow.

Black tea--helpful or harmful? A review of the evidence.

OBJECTIVE: To consider whether consumption of black tea has a positive or negative impact on health. DESIGN: Databases were searched for relevant epidemiological and clinical studies published between 1990 and 2004. RESULTS: Clear evidence was found for coronary heart disease (CHD), where an intake of > or = 3 cups per day related to risk reduction. The mechanism could involve the antioxidant action of tea polyphenols. While experimental models have suggested that flavonoids attenuated cancer risk, epidemiological studies failed to demonstrate a clear effect for tea, although there is moderate evidence for a slightly positive or no effect of black tea consumption on colorectal cancer. Studies on cancer were limited by sample sizes and insufficient control of confounders. There is moderate evidence suggestive of a positive effect of black tea consumption on bone mineral density although studies were few. There is little evidence to support the effect of tea on dental plaque inhibition but evidence to support the contribution of tea to fluoride intakes and thus theoretical protection against caries. There was no credible evidence that black tea (in amounts typically consumed) was harmful. Normal hydration was consistent with tea consumption when the caffeine content was < 250 mg per cup. A moderate caffeine intake from tea appeared to improve mental performance, although sample sizes were small. There was no evidence that iron status could be harmed by tea drinking unless populations were already at risk from anaemia. CONCLUSIONS: There was sufficient evidence to show risk reduction for CHD at intakes of > or = 3 cups per day and for improved antioxidant status at intakes of one to six cups per day. A maximum intake of eight cups per day would minimise any risk relating to excess caffeine consumption. Black tea generally had a positive effect on health.

Retrospective analysis of the impact of a low glycaemic index diet on hospital stay following coronary artery bypass grafting: a hypothesis.

OBJECTIVE: Glucose tolerance and insulin resistance influence medical outcome in subjects with coronary artery disease, these metabolic parameters also influence general perioperative surgical outcome. We hypothesize that glucose tolerance and insulin resistance can be favourably modified by reducing the glycaemic index of the diet. DESIGN: The present study is a retrospective analysis of a low and high glycaemic index diet on glucose tolerance, insulin resistance and perioperative outcome, as assessed by the length of hospital stay following coronary artery bypass surgery. Thirty-five adults awaiting bypass surgery were randomized, for the 4 weeks prior to surgery, to either a low glycaemic index diet (17 subjects) or high glycaemic index diet (18 subjects). Glucose and insulin responses during a 75 g oral glucose tolerance test were assessed before and after dietary intervention and insulin-mediated glucose uptake was assessed in isolated adipocytes obtained at surgery. RESULTS: The patients who consumed a low glycaemic diet had improved glucose tolerance and significantly greater in vitro adipocyte insulin sensitivity at the time of surgery compared with the high glycaemic diet group (78.87 +/- 10.64% versus 41.11 +/- 7%, respectively). The total length of stay in the patients on the low glycaemic diet was less than patients consuming the high glycaemic diet (7.06 +/- 0.38 days versus 9.53 +/- 1.44 days, P < 0.5). CONCLUSION: This study provides further support that carbohydrate and fat metabolism influence cardiac outcome and provides new evidence that dietary modification prior to coronary artery bypass surgery can shorten hospital stay.

Effect of large bowel fermentation on insulin, glucose, free fatty acids, and glucagon-like peptide 1 (7-36) amide in patients with coronary heart disease.

Insulin resistance syndrome has recently been described as a unifying hypothesis to explain the relationship between the many risk factors of coronary heart disease. Carbohydrate that is malabsorbed and fermented in the colon has been demonstrated to decrease insulin response to a glucose load and improve other risk factors associated with coronary heart disease, although the mechanism remains unclear. The object of the present study was to investigate whether this observation could be explained by the production of fermentation products induced by malabsorbed carbohydrate in the colon, or by stimulating the incretin glucagon-like peptide 1 (7-36) amide that is released from the large bowel. We used lactulose as a model for resistant starch carbohydrate. Ten insulin-resistant male volunteers, who had undergone previous coronary artery bypass grafting, volunteered to take part in the study and underwent 6 d of lactulose loading (15 g/d for 2 d and 30 g/d for 4 d). There was no significant change in insulin, glucose, free fatty acids, or glucagon-like peptide 1 (7-36) amide response to an oral glucose tolerance test following the lactulose despite a significant rise in breath hydrogen. Large bowel fermentation stimulated by lactulose appears to have no significant effect on insulin, glucose, free fatty acids, and glucagon-like peptide 1 (7-36) response in patients with coronary heart disease.

Glycaemic index as a determinant of serum HDL-cholesterol concentration.

BACKGROUND: Diet influences the prevalence of coronary heart disease (CHD). Insulin sensitivity and concentrations of HDL cholesterol, two metabolic predictors of CHD, are also influenced by diet. Dietary carbohydrates with a high glycaemic index cause a high postprandial glucose and insulin response, and are associated with decreased insulin sensitivity and an increased risk of CHD. This study examined whether the glycaemic index of dietary carbohydrates is a determinant of serum HDL-cholesterol concentrations. METHOD: Dietary, anthropometric, and biochemical data from the 1986-87 Survey of British Adults (n=2200) were reanalysed by a multiple regression model, which examined the relation between serum total cholesterol, HDL-cholesterol, and calculated LDL-cholesterol concentrations and various dietary characteristics, including the type of carbohydrate, the glycaemic index, and fat intake. FINDINGS: Among the 1420 participants with complete data, there was a significant negative relation between serum HDL-cholesterol concentration and the glycaemic index of the diet for both men (regression coefficient -0.00724 [95% CI -0.0101 to -0.00434], p=0.02) and women (-0.01326 [-0.0162 to -0.0102], p<0.0001). No other significant relation was found with total cholesterol or LDL-cholesterol concentration or with any other dietary carbohydrate or fat constituent. INTERPRETATION: In a cross-sectional study of middle-aged adults, the glycaemic index of the diet was the only dietary variable significantly related to serum HDL-cholesterol concentration. Thus, the glycaemic index of the diet is a stronger predictor than dietary fat intake of serum HDL-cholesterol concentration.

Reduced adipocyte insulin sensitivity in Caucasian and Asian subjects with coronary heart disease.

The association between insulin resistance and coronary heart disease (CHD) is strong in the British Indian-Asian population. Adipocyte metabolism may contribute to both insulin resistance and CHD. We examined insulin-stimulated glucose uptake in adipocytes and in vivo insulin sensitivity using the fasting insulin resistance index (FIRI) in 60 subjects (45 Caucasian and 15 Asian) with CHD and 30 Caucasian subjects without CHD. In 25 CHD subjects (18 Caucasian and 7 Asian), the relationship between adipocyte insulin sensitivity and non-esterified fatty acid (NEFA) suppression to oral glucose was examined. Compared with controls, the CHD subjects had higher values of fasting insulin [51 (46 to 54) pmol l(-1) vs 36 (31 to 41) pmol l(-1) p< 0.01] and FIRI [1.65 (1.5 to 1.79) vs 1.06 (0.89 to 1.23), p < 0.01]. Among the CHD subjects, the Asians had higher values than Caucasian [insulin 58 (48 to 67) pmol l(-1) vs 48 (44 to 53) pmol l(-1) p < 0.01, FIRI 1.89 (1.44 to 2.13) vs 1.62 (1.4 to 1.79), p< 0.01)]. Insulin-stimulated glucose uptake in adipocytes was lower in the CHD than control subjects [56 (50 to 62) vs 115 (75 to 132) attomol min(-1).mm2, p < 0.05], being most reduced among the Asians. It was positively correlated with postprandial NEFA suppression and negatively with insulin release. In conclusion, abnormalities of adipocyte function and insulin sensitivity occur in CHD and may contribute to its aetiology.

Insulin sensitivity in women at risk of coronary heart disease and the effect of a low glycemic diet.

The risk of coronary heart disease (CHD) is influenced by family history, insulin sensitivity (IS), and diet. Adiposity affects CHD and IS. The cellular mechanism of IS is thought to involve the adipocyte cytokine tumor necrosis factor-alpha (TNF-alpha). Insulin-stimulated glucose uptake in isolated subcutaneous and omental adipocytes obtained during elective surgery was measured in 61 premenopausal women, 24 with a parental history (PH) of CHD. In vivo IS was measured using the short insulin tolerance test (SITT) in 28 women, 16 with PH-CHD, before and 3 weeks after randomization to a low glycemic index (LGI) or high glycemic index (HGI) diet. In vitro adipocyte IS and TNF-alpha production was measured following dietary modification. On the habitual diet, in vitro insulin-stimulated glucose uptake in adipocytes as a percentage increase over basal was less in women with PH-CHD than in those without it (presented as the median with 95% confidence limits: subcutaneous, 28% (17% to 39%) v 96% (70% to 120%), P < .01); omental, 40% (28% to 52%) v 113% (83% to 143%), P < .01). In vivo IS in 16 PH-CHD subjects and 12 controls before dietary randomization was similar, and increased in both groups consuming a LGI versus HGI diet (PH-CHD, 0.31 (0.26 to 0.37) v 0.14 (0.10 to 0.24) mmol/L/min, P < .01; controls, 0.31 (0.1 to 0.53) v 0.15 (0.06 to 0.23) mmol/L/min, P < .05). Adipocyte IS was greater in PH-CHD women on a LGI versus HGI diet (subcutaneous, 50% (20% to 98%) v 13% (1% to 29%); omental, 97% (47% to 184%) v 29% (4% to 84%), P < .05). Adipocyte TNF-alpha production was higher in women with versus without PH-CHD (subcutaneous, 0.3 (0.18 to 0.42) v 0.93 (0.39 to 1.30) ng/mL/min; visceral, 0.22 (0.15 to 1.30) v 0.64 (0.24 to 1.1) ng/mL/min, P < .04, respectively), but was uninfluenced by the dietary glycemic index. We conclude that in vitro adipocyte IS is reduced and adipocyte TNF-alpha production is increased in premenopausal women with PH-CHD. A LGI diet improves both adipocyte IS in women with PH-CHD and in vivo IS in women with and without PH-CHD.

Resting blood pressure and cardiovascular reactivity to mental arithmetic in mild hypertensive males supplemented with blackcurrant seed oil.

The objective of this study was to test the effect of a supplement of blackcurrant seed oil (BSO), a rich source of gamma-linolenic acid (C18:3n-6) on the resting blood pressure (BP) and cardiovascular reactivity to a psychological stress in borderline hypertensive individuals. Twenty-seven male volunteers found to have a BP lying persistently within the borderline range, were allocated randomly to one of two groups at the end of a 4-week baseline period. The first group received a daily supplement of 6 g safflower oil for the consecutive 8 weeks while the second the same dose of blackcurrant seed oil. In addition to weekly measurements of resting BP, BP and heart rate reactivity to a standardised 5-min test of mental arithmetic were recorded before, and at the end of the supplementation period. BSO inhibited BP reactivity by over 40% (ANOVA for repeated measures diastolic (D) BP P = 0.026, systolic (S) BP P = 0.021). The decrease in DBP for the subjects on BSO was significantly different from the slight changes observed in the safflower group (ANOVA for repeated measures P = 0.018 for time-treatment interaction). We conclude that gamma-linolenic-rich fatty acid preparations are likely to influence cardiovascular control, by mechanisms yet to be clarified.

The effect of low-glycemic carbohydrate on insulin and glucose response in vivo and in vitro in patients with coronary heart disease.

The insulin resistance syndrome has recently been implicated in the etiology of coronary heart disease, with a possible metabolic defect at the level of the adipocyte. We report the effects of a low- versus high-glycemic-index (LGI and HGI, respectively) diet on insulin and glucose response as assessed by oral glucose tolerance test (OGTT) and insulin-stimulated glucose uptake in isolated adipocytes in a group of 32 patients with advanced coronary heart disease. The area under the insulin curve following OGTT was significantly reduced after 4 weeks in the LGI group (P < .03), but not in the HGI group. Insulin-stimulated glucose uptake in isolated adipocytes harvested from a presternal fat biopsy was significantly greater following the LGI diet (P < .05). This study demonstrates that simple short-term dietary measures can improve insulin sensitivity in patients with coronary heart disease.

Acute effects of mycoprotein on subsequent energy intake and appetite variables.

The effect of mycoprotein, a food produced by continuous fermentation of Fusarium graminearum (Schwabe), on energy intake and appetite was investigated. Female subjects, all classified as nonrestrained eaters, participated in two 3-d study periods. Subjects weighed food consumed on the day before the study, on the day of the meal, and on the following day. Subjects were presented with an isoenergetic meal containing either mycoprotein or chicken and visual analogue scales were completed immediately premeal, postmeal, and at hourly intervals for 3 h. Energy intake was significantly reduced the day of the study (by 24%) and the next day (by 16.5%) after eating mycoprotein compared with chicken. When measured 3 h after consumption, prospective food consumption and desire to eat decreased after mycoprotein compared with chicken. Evidence is increasing that fiber can have an effect on appetite and we have demonstrated that fiber-containing mycoprotein also has this affect.