Loma Linda University

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Joan Sabaté, MD & DrPH
Professor, School of Public Health
School of Public Health
Professor, Medicine
School of Medicine
Member, Epidemiology & Biostats, SPH, Faculty of Graduate Studies
Research & Grantsmanship    Funded Research Project (PI)
  • Data mining the Adventist Health Study-2 information for nut consumption and health outcomes ( 1/2011 - 12/2013 )
    The Adventist Health Study-2 is a prospective epidemiologic study of 97,000 Seventh Day Adventists designed to examine the relationship of lifestyle factors and chronic disease risks.  Data was collected by means of a 2,000 data field, self-administered questionnaire which included over 130 food items.  Among these items detailed information was collected on nut consumption and included frequency and serving size.  This data provides a unique base from which to explore relationships of nut consumption and health outcomes.  The Data Mining Study allowed a full time post doctoral fellow to mine this data and produce two publishable manuscripts.  Questions of nut consumption and obesity, diabetes and metabolic syndrome were explored.  Also of interest was the relation of nut consumption to lifestyle factors and overall diet.
  • Incorporating avocados in meals: Effect on glycemic index, insulin response, satiety and satiety-related gastrointestinal peptides in humans ( 10/2010 - 9/2013 )

    The purpose of this study is to examine the effect of incorporating avocados in meals on post-ingestion glycemic index, insulin response, sensations of satiety and on appetite-related gastrointestinal peptide and hormone release. Also the effect of consuming avocado containing meals on the caloric intake of participants in subsequent eating episodes will be explored.

    Methods
    In this feeding study each subject will participate in one intervention for one day, wait three weeks, come for another intervention, wait three weeks and come for a final intervention- three in total.  Participants will be randomly assigned to one of the six treatment sequences. Postprandial response to the control and two avocado-containing test meals will be assessed and compared using a 3 x 3 single blind cross-over design.

    The Subjects will be between 25 and 54 years old, female or male, with a BMI of 25 to 30, stable weight, no sports involvement, non-smoking and not dependent on caffeine. In total subject participation will last approximately 9 weeks.

    Thirty subjects will be recruited from Loma Linda and surrounding communities. A multi-stage process will be used to select participants. Respondents will fill out a screening form and those qualified will be asked to attend meetings where investigators will provide details and expectations. All participants selected will sign a consent form.
  • Effect of daily ingestion of walnut for 2 years on age-related cognitive decline and macular degeneration in health elderly subjects: a randomized, single blind, dual center, controlled trial

    ( 1/2012 - Present )

    This is a dual center (Loma Linda Univrsity site and Clinic Hospital in Barcelona Site), single blind, randomized, controlled intervention trial. 350 helthy non-demented elderly (ages 63-79 years) participants have been recruited in each of the sites for a total of 700 participants. Following baseline data collection, participants will be randomly assigned to one of each group: walnut group (habitual diet with 1 or 1.5 oz/d walnut supplement based on energy consumption) or control group (habitual diet only). The intrvention will be for 2 years. At bseline and yearly, cardiometabolic risk factors, red blood cell membrane fatty acids, urinary polyphenols and biomarkers of inflammation and oxidation will be measure at both sites. Eye exam and ambulatory blood pressure will be measured at these same time points but oly at the Barcelona site. Cognitive fucntion tests, magnetic resonance imaging (on subset of participants) will be mesured at baseline andyear 2 end at both sites, while in addition, carotid intima-media thickness and dual x-ray absorptiometry will be measure only at the Barcelona site during these two time points.

  • Is soy consumption associated with puberty and health of female adolescents? A cross sectional study ( 9/2011 - Present )

    The purpose of the study was to determine what nutrients, foods, and food groups are associated with age at onset of puberty, rate of pubertal development, and physical stature. Since overweight/obesity and early occurrence of puberty have implications in future (adult) health of adolescents, we were interested in exploring further the relationships between dietary exposure during childhood/adolescence and physical and pubertal development. The procedures included recruiting eligible subjects from selected schools. Data was collected from enrolled subjects by means of an online food frequency questionnaire on current dietary consumption, a questionnaire on pubertal development for boys and another for girls, and a questionnaire on past dietary consumption. Anthropometric data was collected at clinics held on campus at each of the participant schools. Subjects were in 7th through 10th grades (12 to 16 years old), students at selected schools, boys and girls.

  Funded Research Project (CI)
  • Pilot study to assess the acceptability of pearl millet grain at macro and micro levels in rural Eastern Kenya ( 1/2011 - 12/2011 )
  • Effect of walnuts compared to fatty fish on selected markers of bone formation and resorption. ( 0/2009 - 0/2010 )
  Grant Proposals--Funded
  • Data mining the Adventist Health Study-2 information for nut consumption and health outcomes ( 7/2011 - 10/2012 )
    The Adventist Health Study-2 is a prospective epidemiologic study of 97,000 Seventh Day Adventists designed to examine the relationship of lifestyle factors and chronic disease risks. Data was collected by means of a 2,000 data field, self-administered questionnaire which included over 130 food items. Among these items detailed information was collected on nut consumption and included frequency and serving size. This data provides a unique base from which to explore relationships of nut consumption and health outcomes. Questions of nut consumption and obesity, diabetes and metabolic syndrome will be examined. Also of interest is the relation of nut consumption to lifestyle factors and overall diet.
  • Effects of peanut and peanut butter on blood lipids and glycemic control in adults with type-2 diabetes ( 11/2008 - 10/2011 ) Link...
    The prevalence of type 2 diabetes in the United States is approximately 6% of the total population. Insulin resistance, the major defects of diabetes, leads to a two to four times increase in age-adjusted prevalence of coronary artery disease. Epidemiologic findings suggest that there are potential benefits offrequent nut and peanut butter consumption in lowering the risk ofDiabetes in women. Peanuts and peanut butter contain high levels of monounsaturated fat (MUFA), arginine, fiber, phytosterols, resveritrol and vitamin E that have the potential to reduce cardiovascular disease (CVD) risk through improved blood glucose control and favorable modification of blood lipids. When substituted for saturated fat in the diet, MUFA may have important metabolic benefits for persons with diabetes. We will study the effects of a peanut and peanut butter-enriched diet on markers of CVD risk factors in free-living adults with diabetes residing in Southern California. This study’s primary clinical outcome will be HDL-cholesterol. Secondary outcomes will include additional serum lipids (total cholesterol, LDL-cholesterol and triacylglycerol), glucose, HbA1c, and anthropometry (body weight, body composition and waist circumference). This study will provide vital information about the role of peanuts and peanut butter in modulating blood glucose homeostasis and CVD risk factors among adults with diabetes.
  • Incorporating avocados in meals: Effect on glycemic index, insulin response, satiety and satiety-related gastrointestinal peptides in humans. ( 10/2010 - 9/2011 )
    Avocados are a rich source of dietary fiber and fiber is one of the nutritonal components linked to satiety.  Satiety is the feeling of fullness that develops after food has been ingested.  The state of satiety delays the onset of the next meal and reduces food consumption at the next eating occasion. Studies have shown that dietary fiber strongly modules glucose and insulin responses to meals. Gastrointestinal peptides and hormones influence appetite, satiation and weight control.  Their fluctuations following meal consumption is important to understanding satiety, the glucose-insulin responses to meals and fat oxidation. We conducted a randomized, controlled, cross-over feeding study to test the hypothesis that that avocado containing meals decrease the postprandial glycemic and insulinemic response, enhance satiety, decrease caloric intake and influence gastrointestianl peptides and hormones to better control food intake.  Subjects were feed three lunches over three weeks one with no avocado, one with avocado added and one with avocado replacing calories.  Biological, psychological and behavior data was collected.  Glycemic and insulin indices, appetitie rating, energy intake and gastrointestinal peptides and hormones will be analyzed.
  • Postprandial effects of walnut ingestion on plasma concentrations of nutrients, polyphenolic compounds and biomarkers of antioxidant status in human volunteers ( 10/2010 - 9/2011 )
    The consumption of walnuts results in favorable reductions of plasma lipids and lipoproteins. These changes have been attributed to the unique lipid profile of walnuts. However, the health benefits of walnuts may not be limited to blood lipid changes. Walnuts are rich in tocopherols and phenolic substances which may potentially contribute to the body’s antioxidant defenses. Additional lab analysis on serum samples collected from a postprandial intervention conducted in 2009 will be analyzed to determine whether ellagic acid, catechins and tocopherols (vitamin E) found in walnuts are bioavailable and appear in the blood following walnut consumption. It will also be determined whether these substances, once absorbed, impact lipid oxidation and the antioxidant capacity of the blood.
  • A field study in Eastern Province of Kenya (Africa) of traditional meatless diets (cereals, grains, legumes and green vegetables) in prevention of malnutrition in children ( 3/2008 - 3/2011 )
    Background: Ukambani region in Eastern province of Kenya is an arid and semi arid land. Pearl millet was domesticated as a food crop in East Africa about 4000 years ago. Pearl millet has a higher level of heat tolerance than maize. Though pearl millet has been replaced by maize in most parts of Ukambani e.g. Makueni (MA) some parts still use pearl millet e.g. Mwingi (MW) as staple cereal. It is hypothesized that cultivation and consumption of this traditional grain: pearl millet, as opposed to maize results in improved food security and better nourishment for children. Methods: We interviewed 403 mothers to collect dietary information about their children from 4 randomly selected locations in MW and MA. Surrogate 24-hr recalls from 629 children (306 boys and 323 girls) aged < 5 years were obtained. The reported food consumption was classified in food groups for analysis. Total weight and energy contribution of these foods were compared in the two districts using t-test. Results: Mean daily energy intake for children in MW district (1130 kcal) was 15% higher than in MA district (983 kcal). This difference is mainly due to higher intakes of grains in MW as compared to MA. Average (mean+ SD) kcal contribution from grains (872 + 568 kcal) in MW was significantly higher compared to MA (692+ 443 kcal), p< 0.0001 (26 %). All the other foods contribution to kcal was not significantly different in the two districts. Overall, grains contribute 65% of total energy intake. In MW grains (mainly pearl millet) contribute 68 % to total energy while in MA (mainly maize) only 62%. Legumes, tubers and meat contribute a slightly higher % to total energy in MW than MA, while milk, fruits and fats contribute a slightly higher % in MA than MW. Conclusion: Children in Mwingi district a pearl millet region have higher energy consumption from grains as compared to Makueni. Thus, they have better food security due to use of this traditional cereal pearl millet.
  • Vegetarian diet in the prevention of childhood obesity ( 3/2008 - 3/2011 )
    Background: Obesity is becoming a worldwide epidemic. This is particularly critical during childhood and adolescence. Dietary habits and obesity during this period of life have been linked to the development of several chronic diseases, particularly cancer, later in life. Scientists, professional societies and government agencies have placed the issue of childhood obesity prevention high in the priorities of the public health agenda.  Vegetarian diets tend to be low in total energy intake and high in fiber, vitamins, minerals, complex carbohydrates and essential fatty acids, among other nutrients. It is sound to think that a vegetarian diet, followed in the early years will result in lower rates of obesity.  In fact, many adolescents, willing to loose weight, adopt a vegetarian diet spontaneously.  However, this association will be due to reverese causation. Methods: Given the high prevalence of obesity in childhood and adolescence and the negative effects on many health outcomes later in life, this study will assess the effects of a vegetarian diet on the risk of obesity during adolescence.  We will access a large data set of school aged children (7 to 18 years) attending schools in Southern California, with a comprehensive assessment of their dietary habits by food questionnaire and dietary recalls.  The dietary paterns and anthropometric measurements were assessed on about 2,000 children or adolescents for a study of blood pressue conducted in the 1980s with a government grant.  These students had a wide range of dietary patterns varying from vegetarian (1/3) to low-meat eaters (1/3) to regular meat eaters (1/3). We will relate frequency of meat intake and adherence to a vegetarian diet pattern with body weight, body mass index and rate of obesity.
  • Effect of daily ingestion of walnut for 2 years on age-related cognitive decline and macular degeneration in healthy elderly subjects: a randomized, single blind, dual center, controlled trial. ( 10/2011 - Present )