Controlled Dietary Intervention Trial Research Articles

Glycemic control and variability in association with body mass index and body composition over 18 months in youth with type 1 diabetes

AimsThe impact of adiposity on glycemic control in type 1 diabetes patients has important implications for preventing complications. This study examined associations of glycemic outcomes with body mass index (BMI, kg/m2) and body composition in youth with type 1 diabetes. MethodsThis is a secondary analysis of an 18-month randomized controlled dietary intervention trial (N=136, baseline age=12.3±2.5y, HbA1c=8.1±1.0% (65±11mmol/mol)). Measured height and weight every 3months were abstracted from medical records. Body composition was assessed by dual energy X-ray absorptiometry (DXA) at baseline, 12 and 18months. Glycated hemoglobin (HbA1c) and glycemic variability assessed by masked 3-day continuous blood glucose monitoring (CGM) were obtained every 3months. 1,5-Anhydroglucitol (1,5-AG) was assessed every 6months. Adjusted random effects models for repeated measures estimated associations of time-varying BMI and body composition with time-varying glycemic outcomes. ResultsThere was no treatment effect on glycemic outcomes. HbA1c was not associated with BMI or body composition indicators. 1,5-AG was inversely associated with BMI and adiposity indicators (%fat, trunk fat mass and trunk %fat), adjusting for developmental covariates. Adiposity indicators were positively associated with %glucose >180mg/dL and >126mg/dL when adjusting for developmental covariates, and %glucose >126mg/dL when additionally adjusting for diabetes-related covariates. Fewer consistent relationships were observed for 3-day mean glucose and %glucose <70.2mg/dL. BMI and body composition variables were not associated with standard deviation of glycemic values or mean amplitude of glycemic excursions. ConclusionsThe role of greater BMI and adiposity in diabetes management in youth with type 1 diabetes may relate specifically to increased hyperglycemic excursions.

Impact of food supplementation on weight loss in randomised controlled dietary intervention trials: A systematic review

Impact of food supplementation on weight loss in randomised controlled dietary intervention trials: A systematic review

The impact of whole-of-diet interventions on depression and anxiety: a systematic review of randomised controlled trials.

Non-pharmacological approaches to the treatment of depression and anxiety are of increasing importance, with emerging evidence supporting a role for lifestyle factors in the development of these disorders. Observational evidence supports a relationship between habitual diet quality and depression. Less is known about the causative effects of diet on mental health outcomes. Therefore a systematic review was undertaken of randomised controlled trials of dietary interventions that used depression and/or anxiety outcomes and sought to identify characteristics of programme success. A systematic search of the Cochrane, MEDLINE, EMBASE, CINAHL, PubMed and PyscInfo databases was conducted for articles published between April 1971 and May 2014. Of the 1274 articles identified, seventeen met eligibility criteria and were included. All reported depression outcomes and ten reported anxiety or total mood disturbance. Compared with a control condition, almost half (47%) of the studies observed significant effects on depression scores in favour of the treatment group. The remaining studies reported a null effect. Effective dietary interventions were based on a single delivery mode, employed a dietitian and were less likely to recommend reducing red meat intake, select leaner meat products or follow a low-cholesterol diet. Although there was a high level of heterogeneity, we found some evidence for dietary interventions improving depression outcomes. However, as only one trial specifically investigated the impact of a dietary intervention in individuals with clinical depression, appropriately powered trials that examine the effects of dietary improvement on mental health outcomes in those with clinical disorders are required.

Evaluation of calculated energy and macronutrient contents of diets provided in controlled dietary intervention trials by chemical analysis of duplicate portions

The purpose of this study was to investigate whether Dutch food composition databases (Dutch-FCDB) are accurate enough to plan experimental diets with specified amounts of energy and macronutrients. From 2003 to 2012, 10 controlled dietary intervention trials lasting from 2 to 13 weeks were conducted in different seasons. The energy, macronutrients, dietary fibre, water and fatty acids contents of the test diets were calculated with 3 releases of the Dutch-FCDB and compared with the chemically analyzed nutrients in 25 duplicate diets, except for fatty acids which were analyzed in 10 diets. Calculated values of energy and macronutrient content, especially carbohydrates, were higher than values based on analysis. Correlation coefficients ranged from 0.57 for energy to 1.00 for polyunsaturated fatty acids (PUFA). Bland–Altman plots showed considerable differences for the individual diets, limits of agreement (mean ±1.96 SD) were −11.0 to +11.0g/day for protein, −14.2 to +21.6g/day for total fat, −4.8 to +57.0g/day for carbohydrates and −10.7 to +11.5g/day for dietary fibre. We therefore conclude that Dutch-FCDB can be considered accurate enough for planning of experimental diets to be provided in controlled dietary intervention trials.

Interactions between genetic variants and dietary lipid composition: effects on circulating LDL cholesterol in children

Elevated serum low-density lipoprotein (LDL) cholesterol is a predictor of cardiovascular disease events, and the quality of dietary fat is known to influence serum concentrations of LDL cholesterol in children. Interindividual differences in response to diet exist, but the underlying genetic factors remain largely unknown. We aimed to identify genetic variants that modify the variation in serum lipid response to dietary fat quality. We used data from 2 longitudinal Finnish cohorts designed to study risk factors for cardiovascular diseases. Large-scale genotyping was performed with Metabochip in a long-term randomized controlled dietary intervention trial, the Special Turku Coronary Risk Factor Intervention Project (STRIP), for discovery of genetic polymorphisms. The observational Cardiovascular Risk in Young Finns Study (YFS) with genome-wide genetic data was used as a replication sample for the initial findings. Dietary records were used to calculate the ratio of unsaturated to saturated fats. Interaction models and multiple follow-ups were used in the analysis. In the STRIP cohort, a variant within the PARK2 locus, rs9364628, showed moderate interaction with dietary fat quality and a consistent direction of effect in both scans on serum LDL-cholesterol concentration in children aged 5 and 7 y (P < 0.0084 and P < 0.0057, respectively). In the YFS cohort, we were unable to replicate the initial discovery signal, but rs12207186 within the PARK2 locus and dietary lipid quality had a stronger interaction effect on serum LDL-cholesterol concentration (P < 9.44 × 10(-5)) than did rs9364628 in children aged 6 y. This genotyping study involving 2 cohorts of healthy Finnish children indicates a possible interaction between PARK2 variants and dietary fat quality on serum LDL-cholesterol concentration. This trial was registered at clinicaltrials.gov as NCT00223600.

Lifestyle interventions for cardiovascular disease risk reduction: a systematic review of the effects of diet composition, food provision, and treatment modality on weight loss.

The purpose of this systematic review was to evaluate, synthesize, and interpret findings from recent randomized controlled trials (RCTs) of dietary and lifestyle weight loss interventions examining the effects of (1) diet composition, (2) use of food provision, and (3) modality of treatment delivery on weight loss. Trials comparing different dietary approaches indicated that reducing carbohydrate intake promoted greater initial weight loss than other approaches but did not appear to significantly improve long-term outcomes. Food provision appears to enhance adherence to reduction in energy intake and produce greater initial weight losses. The long-term benefits of food provision are less clear. Trials comparing alternative treatment modalities suggest that phone-based treatment produce short- and long-term weight reductions equivalent to face-to-face interventions. The use of Internet and mobile technologies are associated with smaller reductions in body weight than face-to-face interventions. Based on this review, clinical implications and future research directions are provided.

Abstract P105: Dietary Acid Load of a Low Versus a High Protein Diet and Its Effect on Blood Pressure: A Fully Controlled Dietary Intervention Trial

Background: Mild metabolic acidosis may result in elevated blood pressure (BP). Several formulas to estimate dietary acid load have been developed. However, studies in which these formulas have been validated are limited. Objectives: To validate and/or improve existing formulas for dietary acid load and to examine the association between dietary protein, acid load and BP. Methods: We performed a randomized 14d crossover dietary intervention involving 37 healthy subjects (age: 21±2 y) who consumed individualized, isocaloric diets that were either low or high in protein (0.5 versus 2.0 g protein/kg BW/d). Duplicate portions of the provided diets were collected and analysed for energy and nutrients. We used two measures to characterize dietary acid load (i.e. PRAL and NEAP). Urinary Net Acid Excretion (NAE; i.e. titratable acid + ammonium - bicarbonate) was analysed. BP was measured according to standardized procedures. Results: Mean dietary intakes significantly differed between the low and high protein diet, resulting in significantly different acid load values (Table 1, all p&lt;0.001). The correlation between PRAL and NAE was 0.08 in the low protein diet and 0.62 in the high protein diet. For NEAP the correlations were 0.27 and 0.32. PRAL explained 69% of the variance of NAE, which could not be improved by adding other variables to the formula. Systolic BP was 108.4±7.5 and 109.5±8.0 mmHg on the low and high protein diet respectively (p=0.25). Conclusion: PRAL predicts NAE reasonably well in healthy adults for normal to high protein intake. PRAL can be influenced by diet, but this cannot be clearly attributed to protein intake alone. PRAL does not seem to influence short-term BP in healthy adults with normal BP.

Long-term dietary intervention trials: critical issues and challenges

BackgroundThere are many challenges involved in running randomised controlled dietary intervention trials that investigate health outcomes. The aim of this paper was to evaluate the recruitment process, retention of participants and challenges faced in our dairy intervention trial, and to provide strategies to combat the difficulties of running long-term dietary intervention trials.MethodsA 12-month, randomised, two-way crossover study was conducted in overweight adults with habitually low dairy food consumption to assess the effects of a high dairy intake (4 servings of reduced-fat dairy per day) compared with a low dairy intake (1 serving of reduced-fat dairy per day) on measures of cardiometabolic and cognitive health. On completion of the high dairy intake phase, each participant was interviewed about their experience in the trial and responses were used to evaluate the key issues for study participants.ResultsAlthough the recruitment target was achieved, high rates of attrition (49.3%) and difficulties maintaining participant compliance (reported by 37.8% of participants) were major threats to the viability of the study. Factors that contributed to the high attrition included inability to comply with the dietary requirements of the study protocol (27.0%), health problems or medication changes (24.3%) and time commitment (10.8%).ConclusionAttrition and adherence to study requirements present challenges to trials requiring longer-term dietary change. Including a run-in period to further assess the motivation, commitment and availability of participants, maintaining regular contact with participants during control phases, minimising time commitment, providing flexibility with dietary requirements, facilitating positive experiences, and stringent monitoring of diet are some key recommendations for future dietary intervention trials.Trial registrationAustralia and New Zealand Clinical Trials Registry (ACTRN 12608000538347)

The effects of dietary and nutrient interventions on arterial stiffness: a systematic review

Although dietary and nutrient interventions have been extensively studied as a means of improving arterial stiffness, to our knowledge no systematic analysis of the data has been conducted. The aim of the current study was to systematically review the human clinical trial data and qualitatively examine the efficacy of dietary and nutrient interventions in the treatment of arterial stiffness. We systematically searched multiple databases until July 2010 for relevant randomized controlled human clinical trials of common dietary and nutrient interventions in the treatment of arterial stiffness. Located studies were subject to strict inclusion criteria and objectively assessed for scientific quality. Of the 75 relevant studies located, we considered 38 studies to be appropriate for review. Results revealed support for intakes of omega-3 (n-3) fish oils (Cohen's d = 0.21-0.81) and soy isoflavones (Cohen's d = 0.35-0.39) in the treatment of arterial stiffness. There was limited but consistent evidence to suggest that salt restriction (Cohen's d = 0.28-0.37) as well as consumption of fermented-milk products (Cohen's d = 0.15-0.33) that contain bioactive peptides improved arterial stiffness. The evidentiary support for intakes of vitamins, micronutrients, and herbal medicines was insufficient. Limited but consistent evidence suggested that caffeine intake acutely increased arterial stiffness (Cohen's d = 0.34-0.51). Current evidence from several small studies suggests that omega-3 and soy isoflavone supplementation provides an effective means of reducing arterial stiffness. There was little research that explored intakes of herbal medicines or micronutrients in the treatment of arterial stiffness, and this remains an area of potential research.

Effect of a high protein meat diet on muscle and cognitive functions: A randomised controlled dietary intervention trial in healthy men

Recommendations to use other criteria than N-balance for defining protein requirements have been proposed. However, little evidence to support other measures such as physiological functions is available. To investigate the effects of a usual (UP) versus a high protein (HP) diet on muscle function, cognitive function, quality of life and biochemical regulators of protein metabolism. A randomised intervention study was conducted with 23 healthy males (aged 19-31 yrs). All subjects consumed a Usual Protein (UP) diet (1.5 g protein/kg BW) for a 1-wk run-in period before the intervention period where they were assigned to either a UP or a High Protein (HP) diet (3.0 g protein/kg BW) for 3-wks with controlled intake of food and beverages. Blood and urine samples were taken along with measurements of physiological functions at baseline and at the end of the intervention period. The HP group improved their reaction time significantly compared with the UP group. Branched chain amino acids and phenylalanine in plasma were significantly increased following the HP diet, which may explain the improved reaction time. Healthy young males fed a HP diet improved reaction time. No adverse effects of the HP diet were observed. This trial was registered at www.clinicaltrials.gov as NCT00621231.

Carotenoids but not flavonoids are associated with improvements in spatial working memory in younger adults in a flavonoid-rich v. -poor fruit and vegetable intervention study

Findings from animal studies suggest that components of fruit and vegetables (F&V) may protect against, and even reverse, age-related decline(1,2) in aspects of cognitive functioning such as spatial working memory (SWM). Human subjects in vivo and in vitro studies indicate that anti-inflammatory, anti-oxidant and cell-signalling properties of flavonoids and carotenoids, non-nutrient components of F&V, may underpin this protective effect(3–5). The Flavonoid University of Reading Study (FLAVURS), designed to explore the dose-response relationship between dietary F&V flavonoids and CVD, enabled the investigation of such an association with SWM. FLAVURS is an 18-week parallel three-arm randomised controlled dietary intervention trial with four time points, measured at 6-weekly intervals from baseline. Low F&V consumers at risk of CVD aged 26–70 years were randomly assigned to high flavonoid (HF), low flavonoid (LF) or control group. F&V intake increased by two daily 80 g portions every 6 weeks, with either HF or LF F&V, in addition to each participant's habitual diet, while controls maintained their habitual diet. At each visit, participants completed a cognitive test battery with SWM as the primary outcome. The HF group showed significantly higher levels of urinary flavonoids than LF or controls at 12 weeks (P<0.001) as expected, but surprisingly only higher levels than LF at 18 weeks (P<0.01). The LF group showed higher levels of plasma carotenoids than the other groups at 18 weeks (P<0.001). No group differences were found for SWM overall, however, age-group sub-analyses (26–50 and 51–70 years of age) showed differences from 0 to 18 weeks for younger adults, with LF improving significantly more than the other two groups on SWM (P<0.05). As nutritional absorption is known to decrease with age, separate stepwise regressions were performed on the two age groups irrespective of dietary group, with urinary flavonoids and plasma carotenoids as predictors. For younger adults, improved SWM performance from 0 to 18 weeks was associated with higher carotenoid levels, β=0.28, t(55)=2.10, P<0.05, accounting for 7.5% of the variance, R2=0.075, F(1,54)=4.41, P=0.040. For older adults, no between-group SWM differences were found. Findings suggest that F&V-based flavonoids and carotenoids may provide benefits for cognitive function, and that carotenoids in particular may improve cognitive performance in SWM. Given that these benefits were restricted to younger adults, future work is needed to test the reliability of this finding, as well as determine the mechanisms by which age-dependent differences in F&V responsiveness occur.

Oolong tea does not improve glucose metabolism in non-diabetic adults

Studies of the influence of tea on glucose metabolism have produced inconsistent results, possibly because of the lack of dietary control and/or unclear characterization of tea products. Therefore, a double-blind crossover study was conducted in which healthy males (n = 19) consumed each of three oolong tea products or a control beverage as part of a controlled diet. Treatment beverages (1.4 l/day) were consumed for 5 days, followed by assessment of fasting plasma glucose, fasting serum insulin and an oral glucose tolerance test. Tea products included oolong tea, oolong tea with added catechins and oolong tea with added oolong tea polyphenols, and control beverages included caffeinated water and unsupplemented water. On the fifth day of each treatment period, treatment beverages were consumed with a standardized meal, and glucose and insulin responses were assessed for 240 min. No significant differences were detected for fasting plasma glucose, fasting serum insulin, incremental plasma glucose area under the concentration time curve (AUC), total plasma glucose AUC or total serum insulin AUC. Neither oolong tea nor oolong tea supplemented with catechins or other polyphenols produced improved glucose metabolism in healthy adult volunteers on the basis of this highly controlled dietary intervention trial.

Dietary fat modifications and blood pressure in subjects with the metabolic syndrome in the LIPGENE dietary intervention study

Hypertension is a key feature of the metabolic syndrome. Lifestyle and dietary changes may affect blood pressure (BP), but the knowledge of the effects of dietary fat modification in subjects with the metabolic syndrome is limited. The objective of the present study was to investigate the effect of an isoenergetic change in the quantity and quality of dietary fat on BP in subjects with the metabolic syndrome. In a 12-week European multi-centre, parallel, randomised controlled dietary intervention trial (LIPGENE), 486 subjects were assigned to one of the four diets distinct in fat quantity and quality: two high-fat diets rich in saturated fat or monounsaturated fat and two low-fat, high-complex carbohydrate diets with or without 1.2 g/d of very long-chain n-3 PUFA supplementation. There were no overall differences in systolic BP (SBP), diastolic BP or pulse pressure (PP) between the dietary groups after the intervention. The high-fat diet rich in saturated fat had minor unfavourable effects on SBP and PP in males.

Recruiting older people to a randomised controlled dietary intervention trial - how hard can it be?

BackgroundThe success of a human intervention trial depends upon the ability to recruit eligible volunteers. Many trials fail because of unrealistic recruitment targets and flawed recruitment strategies. In order to predict recruitment rates accurately, researchers need information on the relative success of various recruitment strategies. Few published trials include such information and the number of participants screened or approached is not always cited.MethodsThis paper will describe in detail the recruitment strategies employed to identify older adults for recruitment to a 6-month randomised controlled dietary intervention trial which aimed to explore the relationship between diet and immune function (The FIT study). The number of people approached and recruited, and the reasons for exclusion, will be discussed.ResultsTwo hundred and seventeen participants were recruited to the trial. A total of 7,482 letters were sent to potential recruits using names and addresses that had been supplied by local Family (General) Practices. Eight hundred and forty three potential recruits replied to all methods of recruitment (528 from GP letters and 315 from other methods). The eligibility of those who replied was determined using a screening telephone interview, 217 of whom were found to be suitable and agreed to take part in the study.ConclusionThe study demonstrates the application of multiple recruitment methods to successfully recruit older people to a randomised controlled trial. The most successful recruitment method was by contacting potential recruits by letter on NHS headed note paper using contacts provided from General Practices. Ninety percent of recruitment was achieved using this method. Adequate recruitment is fundamental to the success of a research project, and appropriate strategies must therefore be adopted in order to identify eligible individuals and achieve recruitment targets.Trial registration numberISRCTN45031464.

Exercise, energy balance and the shift worker.

Shift work is now common in society and is not restricted to heavy industry or emergency services, but is increasingly found amongst 'white collar' occupations and the growing number of service industries. Participation in shift work is associated with increased body mass index, prevalence of obesity and other health problems. We review the behavioural and biological disturbances that occur during shift work and discuss their impact on leisure-time physical activity and energy balance. Shift work generally decreases opportunities for physical activity and participation in sports. For those shift workers who are able to exercise, subjective and biological responses can be altered if the exercise is taken at unusual times of day and/or if the shift worker is sleep deprived. These altered responses may in turn impact on the longer-term adherence to an exercise programme. The favourable effects of exercise on body mass control and sleep quality in shift workers have not been confirmed. Similarly, recent reports of relationships between sleep duration and obesity have not been examined in a shift work context. There is no evidence that exercise can mediate certain circadian rhythm characteristics (e.g. amplitude or timing) for improved tolerance to shift work. Total energy intake and meal composition do not seem to be affected by participation in shift work. Meal frequency is generally reduced but snacking is increased on the night shift. Unavailability of preferred foods in the workplace, a lack of time, and a reduced desire to eat at night explain these findings. 'Normal' eating habits with the family are also disrupted. The metabolic responses to food are also altered by shift work-mediated disruptions to sleep and circadian rhythms. Whether any interactions on human metabolism exist between timing or content of food intake and physical activity during shift work is not known at present. There are very few randomized controlled studies on the efficacy of physical activity or dietary interventions during shift work. Some favourable effects of such interventions on fatigue levels at work have been reported, but biological and behavioural outcomes relevant to long-term health and energy balance have not been studied adequately. In addition, recruitment and retention of research participants for randomized controlled trials of physical activity or dietary interventions have been very difficult. We present a model of the various behavioural and biological factors relevant to exercise and energy balance during shift work as a framework for future research.

Glycemic response and health—a systematic review and meta-analysis: the database, study characteristics, and macronutrient intakes

BackgroundReduction of dietary glycemic response has been proposed as a means of reducing the risk of diabetes and coronary heart disease. Its role in health maintenance and management, alongside unavailable carbohydrate (eg, fiber), is incompletely understood. ObjectiveWe aimed to assess the evidence relating the glycemic impact of foods to a role in health maintenance and management of disease. DesignWe searched the literature for relevant controlled dietary intervention trials on glycemic index (GI) according to inclusion and exclusion criteria, extracted the data to a database, and synthesized the evidence via meta-analyses and meta-regression models. ResultsAmong literature to January 2005, 45 relevant publications were identified involving 972 subjects with good health or metabolic disease. With small reductions in GI (<10 units), increases in available carbohydrate, energy, and protein intakes were found in all studies combined. Falling trends in energy, available carbohydrate, and protein intakes then occurred with progressive reductions in GI. Fat intake was essentially unchanged. Unavailable carbohydrate intake was generally higher for intervention diets but showed no trend with GI (falling or rising). Among studies reporting on GI, variation in glycemic load was approximately equally explained by variation in GI and variation in available carbohydrate intake. An exchange of available and unavailable carbohydrate (≈1 g/g) was evident in these studies. ConclusionsAmong GI studies, observed reductions in glycemic load are most often not solely due to substitution of high for low glycemic carbohydrate foods. Available carbohydrate intake is a confounding factor. The role of unavailable carbohydrate remains to be accounted for.

Development and testing of a computerised 24-h recall questionnaire measuring fruit and snack consumption among 9–11 year olds

To evaluate the validity, reliability and sensitivity of a computerised single day 24-h recall questionnaire designed for the comparison of children's fruit and snack consumption at the group (school) level. Relative validity and reliability were assessed in relation to (i) intake at school and (ii) intake throughout the whole day, using diary-assisted 24-h recall interviews and a 7-day test-retest procedure. Sensitivity was assessed in relation to intake by comparing results from schools with differing food policies, and by sex. Eight schools took part in the validity and reliability assessments, with 78 children completing the 24-h recall interviews and 195 children completing the test-retest procedure. A total of 43 schools (1890 children) took part in the sensitivity analysis. All children were aged 9-11 y. All schools were in South Wales and South-west England. For fruit intake at school, the questionnaire showed fair levels of validity at the individual level (kappa = 0.29). At the group level, there were little or no differences in fruit intake at school between the two measures and two occasions. The questionnaire was sufficiently sensitive to identify statistically significant differences between girls and boys, and between schools with different food policies. For snack intake at school, validity at the individual level was slightly lower (kappa = 0.220.25), but the data remained of value in analyses at the group level. For fruit and snack intake throughout the whole day there was little agreement at the individual level (kappa = 0.00-0.06), and at the group level there tended to be substantial differences between the two measures and two occasions. The computerised questionnaire is a quick and cost-effective means of assessing children's consumption of fruit at school. While further development is required to improve validity and reliability, it has the potential to be particularly useful in randomised controlled trials of school-based dietary interventions.

Can dietary interventions change diet and cardiovascular risk factors? A meta-analysis of randomized controlled trials.

This study evaluated the effectiveness of dietary advice in primary prevention of chronic disease. A meta-analysis was conducted of 17 randomized controlled trials of dietary behavior interventions of at least 3 months' duration. Results were analyzed as changes in reported dietary fat intakes and biomedical measures (serum cholesterol, urinary sodium, systolic and diastolic blood pressure) in the intervention group minus changes in the control group at 3 to 6 months and 9 to 18 months of follow-up. After 3 to 6 months, mean net changes in each of the five outcomes favored intervention. For dietary fat as a percentage of food energy, the change was -2.5% (95% confidence interval [CI] = -3.9%, -1.1%). Mean net changes over 9 to 18 months were as follows: serum cholesterol, -0.22 (95% CI = -0.39, -0.05) mmol/L; urinary sodium, -45.0 (95% CI = -57.1, -32.8) mmol/24 hours; systolic blood pressure, -1.9 (95% CI = -3.0, 0.8) mm Hg; and diastolic blood pressure, -1.2 (95% CI = -2.6, 0.2) mm Hg. Individual dietary interventions in primary prevention can achieve modest improvements in diet and cardiovascular disease risk status that are maintained for 9 to 18 months.