Christopher D. Gardner

Monounsaturated Versus Polyunsaturated Dietary Fat and Serum Lipids A Meta-analysis

The objective of this study was to examine whether oils high in monounsaturated or polyunsaturated fats have a differential effect on serum lipid levels, using a meta-analytical approach. Fourteen studies (1983 through 1994) were identified that met six inclusion criteria, the primary criterion being that a study have at least two intervention diets that varied in monounsaturated and polyunsaturated fat content but were otherwise similar in total fat, saturated fat, fiber, and dietary cholesterol. Seven studies included a comparable high-saturated fat diet. Standardized effect sizes observed treatment difference in mean end-point lipid levels, divided by the pooled (SD) were calculated for individual studies, then individual effect sizes were pooled. The results indicated no significant differences in total, LDL, or HDL cholesterol levels when oils high in monounsaturated or polyunsaturated fats were compared directly. Triglyceride levels were modestly but consistently lower on the diets high in polyunsaturated fats (P = .05). Replacement of saturated fat with either monounsaturated or polyunsaturated fat led to significant decreases in total and LDL cholesterol (P < .001), and the pooled effect sizes were comparable for either type of unsaturate (effect sizes ranged from -0.64 to -0.68, ie, roughly a decrease of 0.65 mmol/L [25 mg/dL] relative to the high-saturated fat diets). Neither type of unsaturated fat significantly changed HDL cholesterol or triglyceride levels relative to the high-saturated fat diets. In conclusion, the evidence from this meta-analysis strongly indicates there is no significant difference in LDL or HDL cholesterol levels when oils high in either monounsaturated or polyunsaturated fats are exchanged in the diet. Any dietary recommendations for the use of one in preference to the other should be based on outcomes other than serum cholesterol levels.

Nonnutritive Sweeteners: Current Use and Health Perspectives A Scientific Statement From the American Heart Association and the American Diabetes Association

A 2009 American Heart Association scientific statement titled “Dietary Sugars Intake and Cardiovascular Health”1 concluded that current intake of added sugars among Americans greatly exceeds discretionary calorie allowances based on the 2005 US Dietary Guidelines.2 For this reason, the American Heart Association Nutrition Committee recommended population-wide reductions in added sugars intake. The present statement from the American Heart Association and the American Diabetes Association addresses the potential role of nonnutritive sweeteners (NNS) in helping Americans to adhere to this recommendation in the context of current usage and health perspectives. By definition, NNS, otherwise referred to as very low-calorie sweeteners, artificial sweeteners, noncaloric sweeteners, and intense sweeteners, have a higher intensity of sweetness per gram than caloric sweeteners such as sucrose, corn syrups, and fruit juice concentrates. As a caloric sweetener replacement, they are added in smaller quantities; hence, they provide no or few calories. In our current food supply, NNS are widely used in thousands of beverages and other food products such as diet soft drinks, yogurts, desserts, and gum. Food manufacturers often use a blend of NNS or use a blend of sugar and NNS to improve the flavor acceptability of NNS. In developing this scientific statement, the writing group reviewed issues pertaining to NNS in the context of data on consumer attitudes, consumption patterns, appetite, hunger and energy intake, body weight, and components of cardiometabolic syndrome. The objective was to review the literature to determine whether there were adequate data to provide guidance for the use of NNS. The focus of the statement is on the 6 NNS that are described in Table 1. Aspartame, acesulfame-K, neotame, saccharin, and sucralose are regulated as food additives by the US Food and Drug Administration and therefore had to be approved as safe before being marketed. Regarding stevia, …

Promoting Physical Activity Through Hand-Held Computer Technology

BACKGROUND Efforts to achieve population-wide increases in walking and similar moderate-intensity physical activities potentially can be enhanced through relevant applications of state-of-the-art interactive communication technologies. Yet few systematic efforts to evaluate the efficacy of hand-held computers and similar devices for enhancing physical activity levels have occurred. The purpose of this first-generation study was to evaluate the efficacy of a hand-held computer (i.e., personal digital assistant [PDA]) for increasing moderate intensity or more vigorous (MOD+) physical activity levels over 8 weeks in mid-life and older adults relative to a standard information control arm. DESIGN Randomized, controlled 8-week experiment. Data were collected in 2005 and analyzed in 2006-2007. SETTING/PARTICIPANTS Community-based study of 37 healthy, initially underactive adults aged 50 years and older who were randomized and completed the 8-week study (intervention=19, control=18). INTERVENTION Participants received an instructional session and a PDA programmed to monitor their physical activity levels twice per day and provide daily and weekly individualized feedback, goal setting, and support. Controls received standard, age-appropriate written physical activity educational materials. MAIN OUTCOME MEASURE Physical activity was assessed via the Community Healthy Activities Model Program for Seniors (CHAMPS) questionnaire at baseline and 8 weeks. RESULTS Relative to controls, intervention participants reported significantly greater 8-week mean estimated caloric expenditure levels and minutes per week in MOD+ activity (p<0.04). Satisfaction with the PDA was reasonably high in this largely PDA-naive sample. CONCLUSIONS Results from this first-generation study indicate that hand-held computers may be effective tools for increasing initial physical activity levels among underactive adults.

Drinking water is associated with weight loss in overweight dieting women independent of diet and activity.

Background: Data from short‐term experiments suggest that drinking water may promote weight loss by lowering total energy intake and/or altering metabolism. The long‐term effects of drinking water on change in body weight and composition are unknown, however.

Composition, stability, and bioavailability of garlic products used in a clinical trial.

In support of a new clinical trial designed to compare the effects of crushed fresh garlic and two types of garlic supplement tablets (enteric-coated dried fresh garlic and dried aged garlic extract) on serum lipids, the three garlic products have been characterized for (a) composition (14 sulfur and 2 non-sulfur compounds), (b) stability of suspected active compounds, and (c) availability of allyl thiosulfinates (mainly allicin) under both simulated gastrointestinal (tablet dissolution) conditions and in vivo. The allyl thiosulfinates of blended fresh garlic were stable for at least 2 years when stored at -80 degrees C. The dissolution release of thiosulfinates from the enteric-coated garlic tablets was found to be >95%. The bioavailability of allyl thiosulfinates from these tablets, measured as breath allyl methyl sulfide, was found to be complete and equivalent to that of crushed fresh garlic. S-Allylcysteine was stable for 12 months at ambient temperature. The stability of the suspected active compounds under the conditions of the study and the bioavailability of allyl thiosulfinates from the dried garlic supplement have validated the use of these preparations for comparison in a clinical trial.

Replacing sweetened caloric beverages with drinking water is associated with lower energy intake.

Objective: Reduced intake of sweetened caloric beverages (SCBs) is recommended to lower total energy intake. Replacing SCBs with non‐caloric diet beverages does not automatically lower energy intake, however. Compensatory increases in other food or beverages reportedly negate benefits of diet beverages. The purpose of this study was to evaluate drinking water as an alternative to SCBs.

The Effect of a Plant-Based Diet on Plasma Lipids in Hypercholesterolemic Adults: A Randomized Trial

Context People can achieve recommended fat intake while consuming high or low amounts of vegetables, fruits, legumes, and whole grains. Contribution This 4-week randomized trial compared 2 diets with different vegetable, fruit, legume, and whole-grain content but identical total fat, saturated fat, protein, carbohydrate, and cholesterol content. The 59 adults who consumed high amounts of vegetables, fruits, legumes, and whole grains had greater improvements in total and low-density lipoprotein cholesterol levels than the 61 adults who ate low amounts of these foods. Implications At least over the short term, greater improvements in low-density lipoprotein and total cholesterol are an additional benefit of diets high in vegetables, fruits, legumes, and whole grains. The Editors It is well established that elevated low-density lipoprotein (LDL) cholesterol concentrations are a risk factor for cardiovascular diseases and that dietary modification is considered a first approach to their treatment and control (1, 2). For several decades, dietary modification for lipid management traditionally focused on avoiding saturated fat and cholesterol (3-5). Previous examples of dietary interventions targeting LDL cholesterol level often reported only modest lipid improvements, leading some to consider diet a relatively ineffective therapy (6). However, recent developments have suggested that the traditional focus of lipid management may have been overly simplistic and that diets might be more effective if more attention was focused on including certain foods or factors rather than just avoiding saturated fat and cholesterol. Effective refinements of dietary strategies for lipid management could decrease the gap in effectiveness between dietary approaches and drug therapy. Several dietary factors or foods, including soy protein, soy isoflavones, plant sterols, soluble fiber, oats, nuts, and garlic, have established or potential lipid benefits (7-13). Each is derived from plant food sources, and it is inclusion of these factors, rather than avoidance, that is reported to confer benefits. However, given that most plant foods contain low or negligible amounts of saturated fat and that all plant foods are devoid of cholesterol, it follows that a plant-based diet is inherently low in saturated fat and cholesterol. Therefore, it is difficult to distinguish between plasma lipid benefits derived from the actual plant-based dietary components and those derived from avoidance of saturated fat and cholesterol. Several studies have been designed to test the effects on plasma lipids of diets with identical saturated fat and cholesterol intake but varied amounts of 1 or 2 additional dietary components (14-16). Data are more limited on dietary approaches that hold saturated fat and cholesterol intake constant while modifying multiple other dietary components simultaneously (17). Modifying multiple dietary components simultaneously (for example, increasing intake of vegetables, fruits, and low-fat dairy) while holding sodium intake constant has been shown to effectively lower elevated blood pressure in the Dietary Approaches to Stop Hypertension trials (DASH I and II) (18, 19). Testing a parallel approach to refining dietary intervention for lipid management is warranted. In 2000, the American Heart Association (AHA) reported revised dietary guidelines that substantially modified its 1993 and 1996 guidelines (2, 4, 5). All 3 versions of the guidelines recommended keeping saturated fat intake at less than 10% of energy and cholesterol intake below 300 mg/d. A notable modification of the 2000 guidelines was to emphasize foods and overall eating patterns, including increased intakes of vegetables and whole grains (in general, a plant-based diet). It was our hypothesis that a plant-based diet consistent with the revised AHA 2000 guidelines would increase the LDL cholesterol-lowering benefits of the previous AHA Step I guidelines. We theorized that this improvement would be independent of the plant-based diets saturated fat and cholesterol content. Therefore, we designed 2 diets that had identical levels of total fat (30% of energy), saturated fat (10% of energy), and cholesterol (<300 mg/d) but differed substantially in content of nutrient- and phytochemical-dense plant-based foods. The purpose of the study was to determine whether LDL cholesterol-lowering benefits among adults with moderately elevated cholesterol levels would be greater under weight-stable conditions with a plant-based low-fat diet than with a more typical, convenience-oriented low-fat diet that was identical in intake of total fat, saturated fat, and cholesterol. Methods Participants Participants were recruited from the local community, primarily through newspaper advertisements, letters to previous study participants, and flyers sent to university employees. Men and women were invited to enroll if they were 30 to 65 years of age with fasting plasma LDL cholesterol levels of 3.3 to 4.8 mmol/L (130 to 190 mg/dL), fasting plasma triglyceride levels less than 2.83 mmol/L (< 250 mg/dL), body mass index between 19 and 31 kg/m2, and a current diet estimated to derive at least 10% of energy from saturated fat. Pregnant women, persons who smoked, persons with prevalent heart disease or diabetes, or persons who had been using lipid-lowering or blood pressure-lowering medications within the past month (all determined through self-report) were excluded. During the recruitment phase, 1096 individuals were screened by telephone interview and 345 who met the initial inclusion criteria were considered eligible for cholesterol testing. Of these 345 persons, 188 who were found to have eligible concentrations of LDL cholesterol and triglycerides attended an orientation meeting. Fifty-one persons decided not to participate (primarily because of the time commitment), and an additional 12 potential participants were excluded after a 3-day food record showed that their estimated average intake of saturated fat was already less than 10% of energy. One hundred twenty-five participants were randomly assigned to 1 of the 2 diet groups. The Stanford University Human Subjects Committee reviewed and approved the investigation, all participants signed an informed consent form before enrollment, and the study was performed according to Declaration of Helsinki guidelines (20). Design The trial used a parallel design. We randomly assigned participants in blocks of 20 by selecting, without replacement, from a set of indistinguishable envelopes containing 10 assignments to each of the 2 diet groups. Randomization of the envelopes was done by hand, without a computer algorithm. No stratification criteria were used. Each participant was provided with meals, snacks, and beverages on an outpatient basis for 28 days, as described later. Diets Both study diets were designed to provide 30% of energy from total fat, 10% of energy from saturated fat, and approximately 100 mg of cholesterol per 1000 kcal per day. During the menu-designing stage of the study, the nutrient composition of the diets was determined by using the database of Food Processor software, version 7.0 (ESHA Research, Salem, Oregon). Menus were designed by using commonly available foods from local markets. The Low-Fat diet was designed to include many reduced-fat prepared-food items (for example, reduced-fat cheeses, low-fat frozen lasagna, and low-fat and sugar-rich snack foods). In contrast, the Low-Fat Plus diet was designed to include considerably more vegetables, legumes, whole grains, and fruits. Butter, cheese, and eggs were added to the daily menus for the Low-Fat Plus diet, increasing the saturated fat and cholesterol content to match the Low-Fat diet. A 7-day menu cycle was designed for each of the 2 study diets; therefore, each menu was repeated 4 times during the 28 days. The diets included breakfast, lunch, dinner, beverages, and snacks for each day. Each weekday, the participants ate either lunch or dinner at the dining facility of the Stanford General Clinical Research Center. After their on-site meal, they were given coolers that contained meals and snacks to be consumed off-site. On Fridays, participants received weekend meals to be consumed off-site. Appendix Table 1 and Appendix Table 2 list the daily menus. One free-choice evening meal was allowed each weekend. For this meal, participants were given guidelines for choosing low-fat meals consistent with their diet assignments and were required to keep a record of foods consumed. These records were analyzed for nutritional content and were used to determine the impact of the free-choice meals on the overall study diets. Adherence was measured by using daily log sheets kept by participants that tracked incomplete consumption of study foods or consumption of any nonstudy foods. The 28 daily food logs for each participant were examined for deviations from the diets. The energy contribution of each deviation was determined and then totaled for the entire 28-day protocol period. Each of the 14 daily menus (7-day cycle 2 diets) was analyzed chemically for nutrient content before the study and then again during the study (Covance Laboratories, Madison, Wisconsin). The chemical analyses performed before the study confirmed that the average composition of the daily menus provided 30% of energy from total fat, 10% of energy from saturated fat, and approximately 100 mg of cholesterol per 1000 kcal per day. When the 2 diets were first designed, we attempted to match their mono- and polyunsaturated fat content. However, the database used in the design phase was missing values for these nutrients for approximately 20% of the foods. In addition, many of the specific products purchased locally for the study provided incomplete information for the content of these unsaturated fats. The first round of chemical analyses of the diets, performed before enrollment began, indicated a modest discrepancy b

Nonnutritive sweeteners: current use and health perspectives: a scientific statement from the American Heart Association and the American Diabetes Association.

A 2009 American Heart Association scientific statement titled “Dietary Sugars Intake and Cardiovascular Health” (1) concluded that current intake of added sugars among Americans greatly exceeds discretionary calorie allowances based on the 2005 U.S. Dietary Guidelines (2). For this reason, the American Heart Association Nutrition Committee recommended population-wide reductions in added sugars intake. The present statement from the American Heart Association and the American Diabetes Association addresses the potential role of nonnutritive sweeteners (NNS) in helping Americans to adhere to this recommendation in the context of current usage and health perspectives. By definition, NNS, otherwise referred to as very low-calorie sweeteners, artificial sweeteners, noncaloric sweeteners, and intense sweeteners, have a higher intensity of sweetness per gram than caloric sweeteners such as sucrose, corn syrups, and fruit juice concentrates. As a caloric sweetener replacement, they are added in smaller quantities; hence, they provide no or few calories. In our current food supply, NNS are widely used in thousands of beverages and other food products such as diet soft drinks, yogurts, desserts, and gum. Food manufacturers often use a blend of NNS or use a blend of sugar and NNS to improve the flavor acceptability of NNS. In developing this scientific statement, the writing group reviewed issues pertaining to NNS in the context of data on consumer attitudes, consumption patterns, appetite, hunger and energy intake, body weight, and components of cardiometabolic syndrome. The objective was to review the literature to determine whether there were adequate data to provide guidance for the use of NNS. The focus of the statement is on the 6 NNS that are described in Table 1. Aspartame, acesulfame-K, neotame, saccharin, and sucralose are regulated as food additives by the U.S. Food and Drug Administration and therefore had to be approved as safe before being marketed. Regarding stevia, …

Effect of Increasing Dietary Fiber on Plasma Levels of Colon-Derived Solutes in Hemodialysis Patients

BACKGROUND AND OBJECTIVES Numerous uremic solutes are derived from the action of colon microbes. Two such solutes, indoxyl sulfate and p-cresol sulfate, have been associated with adverse outcomes in renal failure. This study tested whether increasing dietary fiber in the form of resistant starch would lower the plasma levels of these solutes in patients on hemodialysis. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Fifty-six patients on maintenance hemodialysis were randomly assigned to receive supplements containing resistant starch (n=28) or control starch (n=28) daily for 6 weeks in a study conducted between October 2010 and May 2013. Of these, 40 patients (20 in each group) completed the study and were included in the final analysis. Plasma indoxyl sulfate and p-cresol sulfate levels were measured at baseline and week 6. RESULTS Increasing dietary fiber for 6 weeks significantly reduced the unbound, free plasma level of indoxyl sulfate (median -29% [25th percentile, 75th percentile, -56, -12] for fiber versus -0.4% [-20, 34] for control, P=0.02). The reduction in free plasma levels of indoxyl sulfate was accompanied by a reduction in free plasma levels of p-cresol sulfate (r=0.81, P<0.001). However, the reduction of p-cresol sulfate levels was of lesser magnitude and did not achieve significance (median -28% [-46, 5] for fiber versus 4% [-28, 36] for control, P=0.05). CONCLUSIONS Increasing dietary fiber in hemodialysis patients may reduce the plasma levels of the colon-derived solutes indoxyl sulfate and possibly p-cresol sulfate without the need to intensify dialysis treatments. Further studies are required to determine whether such reduction provides clinical benefits.

Recent discoveries in inclusive food-based approaches and dietary patterns for reduction in risk for cardiovascular disease.

Purpose of review To discuss new evidence-based dietary recommendations founded on an inclusive food strategy and to address the challenges that are posed by integrating a growing list of heart healthy foods into the diet without increasing energy intake beyond that required to achieve a healthy body weight. Recent findings New food-based dietary recommendations issued by the American Heart Association with the objective of reducing risk for cardiovascular disease (CVD) promote an inclusionary approach. The American Heart Association recommends a variety of foods to target four major goals: achieve a healthy overall diet, achieve a healthy weight, promote desirable lipid levels, and promote desirable blood pressure. Specific foods recommended include fruits and vegetables, grain products (including whole grains), fish, lean meat and poultry, fat-free or low-fat dairy products, and legumes. In addition, the new National Cholesterol Education Program Adult Treatment Panel III recommends reductions in saturated fat and cholesterol and therapeutic dietary options for enhancing LDL-cholesterol lowering, with inclusion of plant stanols/sterols (2 g/day) and increased viscous (soluble) fiber (10-25 g/day). In parallel with the evolution of new dietary recommendations is the expanding list of specific foods that have cardioprotective effects. Additional foods on this list are nuts, soy, legumes, alcohol, tea, and garlic. Summary It will be challenging to include all foods that reduce CVD risk in the diet and still maintain energy control. Strategies are needed that facilitate developing heart healthy dietary patterns that maximally reduce CVD risk.