Simin Nikbin Meydani

Tufts University | Tufts · Office of the Vice Provost

Background/Objective Obesity increases maternal morbidity and adversely affects child health. Maternal inflammation may play a role in adverse outcomes. The objective of this study was to determine whether providing a higher dose of antioxidant micronutrients to pregnant women with obesity would raise concentrations of key antioxidant vitamins and...

Pneumonia is a major public health problem for older adults, being one of the leading causes of hospitalization and death, particularly for elderly nursing home residents. We previously conducted a clinical trial in which we demonstrated that 29% of nursing home residents had low serum zinc levels coinciding with a two-fold increase in pneumonia in...

Objective Epidemiological studies suggest that consumption of fruits and vegetables (FV) is negatively associated with the incidence of certain cancers and mortality. However, a causal relationship has not been demonstrated. Thus, we investigated the effect of life-long consumption of high level of FV on median lifespan, key biological functions, a...

Introduction The safety of novel forms of iron in healthy, iron-replete adults as might occur if used in population-based iron supplementation programs was examined. We tested the hypotheses that supplementation with nanoparticulate iron hydroxide adipate tartrate (IHAT), an iron-enriched Aspergillus oryzae product (ASP), or ferrous sulphate heptah...

Immunosenescence is a term used to describe the age-related changes in the immune system. Immunosenescence is associated with complex alterations and dysregulation of immune function and inflammatory processes. Age-related changes in innate immune responses including alterations in chemotactic, phagocytic, and natural killing functions, impaired an...

Streptococcus pneumoniae (pneumococcus) resides asymptomatically in the nasopharynx but can progress from benign colonizer to lethal pulmonary or systemic pathogen. Both viral infection and aging are risk factors for serious pneumococcal infections. Previous work established a murine model that featured the movement of pneumococcus from the nasopha...

The forms of iron currently available to correct iron deficiency have adverse effects, including infectious diarrhea, increased susceptibility to malaria, inflammation and detrimental changes to the gut microbiome. These adverse effects limit their use such that the growing burden of iron deficiency has not abated in recent decades. Here, we summar...

Background: Epidemiologic studies suggest that fruit and vegetable (F&V) consumption is inversely associated with incidence of cardiovascular disease (CVD). However, evidence for causality is lacking, and the underlying mechanisms are not well understood. Objectives: We aimed to determine whether there is a causal relation between consuming high...

Significance The elderly exhibit susceptibility to many infectious agents, including S. pneumoniae . A robust acute inflammatory response to S. pneumoniae is associated with severe disease. S. pneumoniae triggers canonical autophagy in nonprofessional phagocytes, but its role in macrophages is largely unexplored. We found that BMDMs utilize LAP, ra...

Background: Epidemiological studies suggest that higher fruits and vegetables (F&V) consumption correlates with reduced risk of hepatic steatosis, yet evidence for causality and the underlying mechanisms is lacking. Objectives: We aimed to determine the causal relation between F&V consumption and improved metabolic disorders in mice fed high-fat...

Streptococcus pneumoniae (pneumococcus) resides asymptomatically in the nasopharynx but, as a pathobiont, can progress from benign colonizer to lethal pulmonary or systemic pathogen. Both viral infection and aging are risk factors for serious pneumococcal infections. Previous work established a murine model that featured the movement of pneumococcu...

Objectives Dementia and cognitive decline are typical age-related neurological disorders. However, obesity has been linked to premature senescence manifestations in various systems including the central nervous system. Nutritional interventions play a role in curbing obesity-associated disorders. Epidemiological studies suggest that increased consu...

Objectives A double-blind, placebo-controlled, randomized clinical trial was conducted to determine the effects of different modalities of supplementation with ferrous sulfate (FeSO4)-iron on the safety profiles of non-anemic, healthy adults. Methods Eligible volunteers (194) were screened for general health; 108 were enrolled and randomized to fo...

Objectives Previously we showed that supplementing a high fat diet (HFD) with a freeze-dried powder of 24 commonly consumed fruits and vegetables (F&V) prevented HFD-induced non-alcoholic fatty liver disease (NAFLD). Since the experimental diets were isocaloric with major difference being in their antioxidant content, we hypothesized that the obser...

Autoimmune diseases are a host of diseases characterized by abnormal immune response against normal tissues of the body. There are about 100 autoimmune diseases, and they are estimated to affect at least 3%–5% of population. While the etiology is still unclear, both genetic and environmental factors are recognized to play key roles in the disease d...

The forms of iron currently available to correct iron deficiency have adverse effects, including infectious diarrhea, increased susceptibility to malaria, inflammation and detrimental changes to the gut microbiome. These adverse effects limit their use such that the growing burden of iron deficiency has not abated in recent decades. Here, we summar...

Objectives: Osteoporosis is a debilitating disease that increases with age and is characterized by increased bone fragility. However, dietary factors can influence the development of osteoporosis. For example, high fat diets (HFD) have been shown to have detrimental effects on bone density and quantity. However, the effects of HFD on bone microarc...

Objectives: Obesity during pregnancy is associated with inflammation and oxidative stress and concomitant depletion of nutritional antioxidant defenses, which may be implicated in adverse perinatal and long-term childhood outcomes. The objective of this study is to determine whether providing a BMI-based prenatal vitamin (BMI-PNV) to pregnant wome...

Objectives: Fecal biomarkers have emerged as an important tool to assess intestinal inflammation and permeability. Commonly measured biomarkers include calprotectin (CP), myeloperoxidase (MPO), alpha-1-antitrypsin (AAT) and neopterin (NEO). We sought to develop a simple, fast and cost-effective single extraction procedure for use in determining al...

Objectives: Epidemiological studies have shown that consumption of fruits and vegetables (F&V) is inversely associated with incidence of cardiovascular disease (CVD). However, the evidence for causality and underlying mechanisms is lacking. Our objective was to determine if increased consumption of F&V could prevent atherosclerosis and its underly...

Objectives: Maternal high-fat (HF) diet predisposes offspring to metabolic syndrome, in part, by inducing alterations during placental development resulting in abnormal fetal development and offspring birth weight. We previously reported in a rat model that a maternal malnutrition diet increases fetal inflammation, and placental vascularization, a...

Aging is associated with significant changes in the immune system, a phenomenon called immunosenescence, which has been implicated in the increased morbidity of, and mortality from, infection in the elderly. While many immune functions are affected by aging, the defects in T cells are the most pronounced and best characterized. Nutritional interven...

It is well-established that the nutritional deficiency or inadequacy can impair immune functions. Growing evidence suggests that for certain nutrients increased intake above currently recommended levels may help optimize immune functions including improving defense function and thus resistance to infection, while maintaining tolerance. This review...

Vitamin E, a potent lipid‐soluble antioxidant, found in higher concentration in immune cells compared to other cells in blood, is one of the most effective nutrients known to modulate immune function. Vitamin E deficiency has been demonstrated to impair normal functions of the immune system in animals and humans, which can be corrected by vitamin E...

The global population, including the United States, is experiencing a demographic shift with the proportion of older adults (aged ≥ 65 years) growing faster than any other age group. This demographic group is at higher risk for developing nutrition-related chronic conditions such as heart disease and diabetes as well as infections such as influenza...

Current vitamin E requirements are uniformly applied across the population for those >14 y of age. However, aging is associated with alterations in cellular and physiologic functions, which are affected by vitamin E. Therefore, it is questionable whether vitamin E requirements can be uniformly applied to all adult age categories. With aging, there...

Blueberry, rich in antioxidant and anti-inflammatory phytochemicals, has been demonstrated to lower inflammatory status in adipose induced by high-fat diet (HFD) and obesity. The effect of blueberry on systemic immune functions has not been examined. C57BL/6 mice were randomised to one of three diets – low-fat diet (LFD), HFD and HFD plus 4 % (w/w)...

Altered regulation of vitamin D metabolites, 25-hydroxyvitamin D (25(OH)D) and 1,25-dihydroxyvitamin D (1,25(OH)2D), was observed in high fat diet (HFD)-induced obesity. We hypothesized that these HFD-induced changes in vitamin D metabolism would be reversed by decreasing fat mass through dietary intervention. Four-week-old C57BL/6 J mice were assi...

Autoimmune disease is highly prevalent in humans. Since conventional therapies have limited efficacy and often come with significant side effects, nutrition may provide an alternative and complementary approach to improving autoimmune disorders. Naringenin, a flavonoid found in citrus fruits, has been shown to have anti-inflammatory and antioxidant...

Background: Emerging evidence suggests novel roles for bacterially derived vitamin K forms known as menaquinones in health and disease, which may be attributable in part to anti-inflammatory effects. However, the relevance of menaquinones produced by gut bacteria to vitamin K requirements and inflammation is undetermined. Objective: This study aime...

Despite the availability of vaccines, Streptococcus pneumoniae remains a leading cause of life-threatening infections, such as pneumonia, bacteremia and meningitis. Polymorphonuclear leukocytes (PMNs) are a key determinant of disease course, because optimal host defense requires an initial robust pulmonary PMN response to control bacterial numbers...

Studies have suggested that obesity is associated with immune dysfunction and higher risk of infection. Maternal obesity is thought to affect body weight which may in turn alter immune function in offspring. However, the relative contribution of maternal factors (maternal obesity versus high fat diet during pregnancy and lactation) to the changes i...

Background: The effect of whole grains on the regulation of energy balance remains controversial. Objective: We aimed to determine the effects of substituting whole grains for refined grains, independent of body weight changes, on energy-metabolism metrics and glycemic control. Design: The study was a randomized, controlled, parallel-arm controlled...

Background: Observational studies suggest an inverse association between whole-grain (WG) consumption and inflammation. However, evidence from interventional studies is limited, and few studies have included measurements of cell-mediated immunity.Objective:We assessed the effects of diets rich in WGs compared with refined grains (RGs) on immune and...

In this consensus statement on immunonutrition and exercise, a panel of knowledgeable contributors from across the globe provides a consensus of updated science, including the background, the aspects for which a consensus actually exists, the controversies and, when possible, suggested directions for future research.

A projected doubling in the global population of people aged ≥60 y by the year 2050 has major health and economic implications, especially in developing regions. Burdens of unhealthy aging associated with chronic noncommunicable and other age-related diseases may be largely preventable with lifestyle modification, including diet. However, as adults...

Calorie restriction (CR) inhibits inflammation and slows aging in many animal species, but in rodents housed in pathogen-free facilities, CR impairs immunity against certain pathogens. However, little is known about the effects of long-term moderate CR on immune function in humans. In this multi-center, randomized clinical trial to determine CR's e...

High-fat diet (HFD)-induced obesity has been reported to result in low hepatic iron storage. In the current study, we tested the hypothesis that these obesity-related changes in hepatic iron status could be reversed by decreasing adiposity by feeding a low-fat diet. Five-week-old C57BL/6 mice were assigned to three groups: The LL group was fed a co...

This review deals with the expectations of vitamin E ability of preventing or curing, as a potent antioxidant, alleged oxidative stress based ailments including cardiovascular disease, cancer, neurodegenerative diseases, cataracts, macular degeneration and more. The results obtained with clinical intervention studies have highly restricted the rang...

Previously, we showed that high fat diet (HFD)‐induced obesity resulted in lower hepatic iron storage. To further investigate the effect of diet‐induced increase in adiposity on hepatic iron storage level and determine whether these obesity‐related changes could be reversed by decreasing fat mass through feeding a low fat diet, we compared hepatic...

Previously, we showed that high fat diet (HFD)‐induced obesity altered expression of vitamin D metabolizing enzymes resulting in higher serum 1,25(OH) 2 D levels. In the current study, we determined whether the HFD‐induced changes in vitamin D metabolism could be restored by decreasing fat mass through changing from a HFD to a lower fat diet. Five‐...

Observational studies suggest an association between diets rich in whole grains (WG) and a decrease in inflammatory markers. Yet, this is not clearly supported by the conflicting or limited number of interventional studies, few of which have included markers of cell‐mediated immunity, which are important functional aspects of the immune system. Fur...

Recent studies have suggested that obesity may be associated with impaired immune function as well as the related reduction in resistance to infection. The most commonly utilized animal model for diet‐induced obesity involves feeding mice a high fat (HF) diet (typically providing 45% or 60% Calories as fat). Since HF diets are also known to affect...

Several epidemiological studies reported an association between a diet rich in whole grains (WG) and reduced risk of cardiovascular disease (CVD). Diets rich in WG may decrease the risk of CVD through the effects of b‐glucan, which slows carbohydrate absorption and lowers LDL cholesterol and total cholesterol by reducing reabsorption of bile acids....

Whole grain‐rich diets are consistently associated with lower adiposity in observational studies. However, clinical trials have failed to substantiate this association or identify underlying mechanisms. The inconsistency has been suggested to be due to trial methodology including suboptimal dietary control and confounding due to body weight changes...

Background: Zinc is essential for the regulation of immune response. T cell function declines with age. Zinc supplementation has the potential to improve the serum zinc concentrations and immunity of nursing home elderly with a low serum zinc concentration. Objective: We aimed to determine the effect of supplementation with 30 mg Zn/d for 3 mo o...

Abstract Observational studies suggest an association between diets rich in whole grains (WG) and a decrease in inflammatory markers. Yet, this is not clearly supported by the conflicting or limited number of interventional studies, few of which have included markers of cell-mediated immunity, which are important functional aspects of the immune sy...

Young-onset calorie restriction (CR) in rodents decreases serum IGF-1 concentration and increases serum corticosterone levels, which have been hypothesized to play major roles in mediating its anticancer and anti-aging effects. However, little is known on the effects of CR on the IGF-1 system and cortisol in humans. To test the sustained effects of...

Both aging and obesity are related to dysregulated immune function, which may be responsible for increased risk of infection and also chronic non-infectious diseases. Dietary lipids have been shown to impact immune and inflammatory responses and cardio-metabolic risk factors. No information on the impact of olive oil on immune responses of overweig...

Caloric restriction (CR), energy intake reduced below ad libitum (AL) intake, increases life span in many species. The implications for humans can be clarified by randomized controlled trials of CR. To determine CR's feasibility, safety, and effects on predictors of longevity, disease risk factors, and quality of life in nonobese humans aged 21-51...

An increasing recognition has emerged of the complexities of the global health agenda-specifically, the collision of infections and noncommunicable diseases and the dual burden of over- and undernutrition. Of particular practical concern are both 1) the need for a better understanding of the bidirectional relations between nutritional status and th...

Streptococcus pneumoniae infections are an important cause of morbidity and mortality in older patients. Uncontrolled neutrophil-driven pulmonary inflammation exacerbates this disease. To test whether the α-tocopherol (α-Toc) form of vitamin E, a regulator of immunity, can modulate neutrophil responses as a preventive strategy to mitigate the age-a...

Numerous studies have provided evidence suggesting that aging is associated with significant adverse changes in the immune system, a phenomenon often called immunosenescence, which may be responsible for an observed increase in morbidity and mortality from infectious disease and cancer in the elderly. While a variety of immune cells are known to be...

Yogurt consumption has been associated with health benefits in different populations. Limited information, however, is available on nutritional and health attributes of yogurt in older adults. Yogurt is abundant in calcium, zinc, B vitamins, and probiotics; it is a good source of protein; and it may be supplemented with vitamin D and additional pro...

The Dietary Guidelines for Americans (DGA) recommend three daily servings of low- or nonfat dairy products, yet two-thirds of individuals in the United States do not meet that goal. Including low- or nonfat yogurt as part of an overall healthful diet can be a positive step toward meeting the DGA recommendations. Yogurt naturally contains calcium an...

It has been hypothesized that micronutrient levels play a role in the immune response to vaccination; however, population-level research on the association between micronutrient levels and immune response to influenza vaccination is needed. In this study, we hypothesized that decreasing levels of nutrients would be associated with decreased hemaggl...

Objective: Little is known about the effect of obesity on inflammatory status in pregnant women. The objective of this study was to determine the effect of obesity on markers of inflammation, oxidative stress and micronutrient status in obese pregnant women and their infants compared with lean controls (Lc). Study design: This was a prospective...

Current vaccines for influenza do not fully protect the aged against influenza infection. Although wolfberry (goji berry) has been shown to improve immune response, including enhanced antibody production, after vaccination in the aged, it is not known if this effect would translate to better protection after influenza infection, nor is its underlyi...

We previously showed that dietary white button mushrooms (WBMs) enhanced natural killer cell activity and that in vitro WBM supplementation promotes maturation and function of dendritic cells (DCs). The current study investigated whether WBM consumption would enhance pathogen-specific immune response using a Salmonella vaccination and infection ani...

Iron status and immune response become impaired in situations that involve chronic inflammation, such as obesity or aging. Little is known, however, about the additional burden that obesity may place on the iron status and immune response in the elderly. This question is relevant given the rising numbers of elderly obese (BMI >30 kg/m(2)) individua...

Provision of fortified juices may provide a convenient method to maintain and increase blood fat-soluble vitamins. To determine whether children consuming orange juice fortified with calcium and combinations of vitamins D, E, and A could increase serum 25-hydroxyvitamin D [25(OH)D], α-tocopherol, and retinol levels. A 12-week randomized, double-bli...