Carl L Keen

• Ph.D.
• Professor (Full) at University of California, Davis

Strawberries provide a number of potential health promoting phytonutrients to include phenolics, polyphenols, fiber, micronutrients and vitamins. The objective of this review is to provide a comprehensive summary of recent human studies pertaining to the intake of strawberry and strawberry phytonutrients on human health. A literature search conduct...

There is a need for transformational innovation within the existing food system to achieve United Nations Sustainable Development Goal 2 of ending hunger within a sustainable agricultural system by 2030. Mycelium, the vegetative growth form of filamentous fungi, may represent a convergence of several features crucial for the development of food pro...

Moderate red wine intake has been associated with lower cardiovascular mortality, due in part to the intake of polyphenols and anthocyanins, whose content can vary from varietal and year of harvest. This study assessed the vascular effects in response to a single intake of 2015 and 2018 Zweigelt red wines from Hokkaido, Japan. Healthy men were rand...

Consumption of nuts and berries are considered part of a healthy eating pattern. Nuts and berries contain a complex nutrient profile, consisting of essential vitamins and minerals, fiber, polyunsaturated fatty acids, and phenolics in quantities that improve physiological outcomes. The spectrum of health outcomes that may be impacted by the consumpt...

Research continues to provide compelling insights into potential health benefits associated with diets rich in plant-based natural products (PBNPs). Coupled with evidence from dietary intervention trials, dietary recommendations increasingly include higher intakes of PBNPs. In addition to health benefits, PBNPs can drive flavor and sensory percepti...

Lutein, zeaxanthin, and meso-zeaxanthin are three xanthophyll carotenoid pigments that selectively concentrate in the center of the retina. Humans cannot synthesize lutein and zeaxanthin, so these compounds must be obtained from the diet or supplements, with meso-zeaxanthin being converted from lutein in the macula. Xanthophylls are major component...

Age-related macular degeneration (AMD) is the third leading cause of blindness worldwide. Macular pigment optical density (MPOD), a biomarker for AMD, is a non-invasive measure to assess risk. The macula xanthophyll pigments lutein (L) and zeaxanthin (Z) protect against blue light and provide oxidant defense, which can be indexed by MPOD. This stud...

The potential of micronutrients to ameliorate the impact of prenatal alcohol exposure (PAE) on attentional regulation skills was explored in a randomized clinical trial conducted in Ukraine. Women who differed in prenatal alcohol use were recruited during pregnancy and assigned to one of three groups (No study-provided supplements, Multivitamin/Min...

The potential role of plant-based foods in the promotion of skin health is an emerging area of nutrition research. Plant-based foods are rich in bioactive compounds, including vitamin C, vitamin E, beta-carotene, polyphenols, and phenolic acids, which can contribute to oxidant defense, lower inflammation, and promote structural support of the skin....

Age-related macular degeneration (AMD) is the third leading cause of blindness worldwide. Macular pigment optical density (MPOD), a biomarker for AMD, is a non-invasive measure to assess risk. The macula xanthophyll pigments lutein (L) and zeaxanthin (Z) protect against blue light and provide oxidant defense, which can be indexed by MPOD. This stud...

Background: Children often consume up to 30% of calories from snacks that are usually low in nutrient value. Over time, poor dietary choices can contribute to an increased risk of obesity and related health problems. Purpose: Describe the development and utilization of the Self-paced Nutrition Activity on Choices for Knowledge (S.N.A.C.K.) nutritio...

Objectives To assess the short-term intake of 39 g freeze-dried strawberry powder (FDSP), compared to an isocaloric control powder, on microvascular function and to determine the relationship with gut microbial composition and select microbial-derived metabolites from feces, serum, and urine. Methods Data were collected from overweight/obese postm...

Cardiovascular disease is a leading cause of death globally, presenting an immense public and economic burden. Studies on cardioprotective foods and their bioactive components are needed to address both personal and public health needs. Date fruit is rich in polyphenols, particularly flavonoids, certain micronutrients, and dietary fiber, which can...

The potential cardiovascular benefit of virgin olive oil (VOO) is widely recognized. However, the use of VOO at very high cooking temperatures makes these oils poorly suited for many Asian dishes. The use of tea seed oil (TSO) is increasing in Thailand, with TSO having a higher smoke point than VOO. The current study examines the effects of daily T...

Mangos are rich in β-carotene and other carotenoids, along with several phenolic acids that may provide oxidant defense and photoprotection to the skin. The objectives of this study are to investigate the effects of Ataulfo mango intake on the development of facial wrinkles and erythema. A randomized two-group parallel-arm study was conducted to as...

Objectives To investigate the effects of mango intake on skin wrinkles (SW) and skin carotenoids (C) in postmenopausal women. Methods A randomized, two-arm parallel study was conducted to assess 16 weeks (wk) of mango intake on SW development in the left and right lateral canthus (crow's feet) of healthy postmenopausal women, aged 50 to 70. Partic...

Objectives Zeaxanthin (Z) and lutein (L) are xanthophyll carotenoids that function in part as macular pigments. Goji berries (Lycium Barbarum) are rich in zeaxanthin, and contain lutein, β-carotene, and β-cryptoxanthin. High intakes of Z and L have been associated with reduced risk of age-related macular degeneration. We assessed the impact of 3 mo...

Objectives This study assessed the influence of short-term freeze-dried strawberry powder (FDSP) intake on gut microbial composition and select microbial-derived metabolites from feces, serum, and urine, and determine their relationship to microvascular function. Methods In this double-blind, controlled crossover study, postmenopausal overweight o...

Objective: Polyunsaturated fatty acids are vital for optimal fetal neuronal development. The relationship between maternal alcohol consumption and smoking with third trimester plasma fatty acids were examined and their association with Fetal Alcohol Spectrum Disorders (FASD). Methods: Moderate to heavy alcohol-using and low/unexposed comparison wom...

Walnut consumption can provide both vascular and metabolic health benefits, and walnut-induced changes in lipoprotein particle chemical payloads may be responsible for these health benefits. To explore this possibility with a focus on metabolic health, this study investigated the impact of walnut consumption on lipoprotein lipid composition and cha...

There is increasing appreciation that dietary components influence and interact with genes important to metabolism. How such influences impact developmental regulation and programming or risks of chronic diseases remains unclear. Nutrition is recognized to affect development and chronic diseases, but our understanding about how genes essential to n...

Background & aims: Stunting in children is a comorbid condition in undernutrition that may be ameliorated by the provision of high-quality foods that provide protein and micronutrients. Addressing this problem in lower social economic environments requires, in part, affordable and scalable food-based solutions with efficacious food products. Towar...

Background: Legumes are an excellent plant source of the limiting indispensable amino acid (IAA) lysine in vegetarian, cereal-based diets. However, their digestibility is poor largely because of their antiprotease content. Extrusion can enhance digestibility by inactivating trypsin inhibitors and thus potentially improve the protein quality of leg...

Cardiovascular disease is a leading cause of death in the United States and much of the developed world, costing billions of dollars in lost work time, lower productivity and high health care expenditures. Research on foods and bioactive food components that have cardioprotective benefits may provide new insights as to how modest changes in one's d...

Osteoporosis and cardiovascular disease are global health burdens, with postmenopausal women being at great risk. Dried plums/prunes (DPs) have been reported to provide bone health benefits in animal models, which is consistent with in vitro models. Data from human studies suggest that DP intake can enhance lipid metabolism, anti-inflammatory, and...

Background/Objective: Polyunsaturated fatty acids (PUFA) are vital for optimal fetal neuronal development. This study examined the relationship between maternal alcohol consumption and smoking with plasma fatty acids measured in the third trimester and their association with Fetal Alcohol Spectrum Disorders (FASD). FASD is an umbrella term used to...

Objectives: Dietary nitrate, provided by certain vegetables, may serve as a potential source of the potent vasodilator nitric oxide (NO). This may be of importance in situations of reduced blood flow or increased tissue oxygen demand, such as during tissue ischemia or exercise. This study tested the effects of a nitrate-rich vegetable juice, provi...

An individual's diet affects numerous physiological functions and can play an important role in reducing the risk of cardiovascular disease. Epidemiological and clinical studies suggest that dietary flavanols can be an important modulator of vascular risk. Diets and plant extracts rich in flavanols have been reported to lower blood pressure, especi...

Excessive alcohol consumption has been shown to increase serum plasma levels of numerous immune cytokines. Maternal immune activation and elevated cytokines have been implicated in certain neurological disorders (e.g., autism and schizophrenia) in the offspring. We investigated the hypothesis that elevated cytokines during pregnancy are a risk fact...

Objectives: Fatty acid profiles and desaturase (SCD-16, SCD018, D5D, D6D) and elongase (ELOVL6) enzyme activity have been associated with adiposity and metabolic disease. While this has been studied in adults, few studies have included children. The objective of this study was to evaluate these markers in children and identify relationships with m...

Objective: To evaluate the effectiveness of the Shaping Healthy Choices Program (SHCP). Design: A clustered, randomized, controlled intervention lasting 1 school year. Setting: Schools in northern and central California. Participants: Fourth-graders (aged 9-10 years) at 2 control schools (n = 179) and 2 intervention schools (n = 230). Inter...

Objective: Heavy alcohol consumption can alter vitamin D status; however, the relationships between alcohol consumption and vitamin D concentrations in pregnant women have not been well studied. The aim of this study was to investigate the vitamin D status in a population of alcohol-exposed (N = 180) and low/unexposed control (N = 179) Ukrainian p...

In the United States, as in most of the world, there are large numbers of nutraceuticals that are sold and which people take to boost their immune response. There are, in addition, almost an equal number of products sold to reduce allergies. However, very few consumers, and indeed physicians, are aware of what a structure/function claim is. Structu...

Objective: To determine whether fourth-grade students participating in the Shaping Healthy Choices Program (SHCP), a school-based nutrition intervention, would change vegetable and carotenoid intake measured by skin carotenoids and dietary intake. Methods: Single-group pretest-posttest with a self-selected, convenience sample of students (n = 30...

Wilson disease (WD), a genetic disorder affecting copper transport, is characterized by hepatic and neurological manifestations with variable and often unpredictable presentation. Global DNA methylation in liver was previously modified by dietary choline in tx-j mice, a spontaneous mutant model of WD. We therefore hypothesized that the WD phenotype...

Diet is a major life style factor affecting human health, thus emphasizing the need for evidence-based dietary guidelines for primary disease prevention. While current recommendations promote intake of fruit and vegetables, we have limited understanding of plant-derived bioactive food constituents other than those representing the small number of e...

Previous studies have shown that the intake of freeze-dried strawberry powder (FDSP) improves select markers of cardiovascular health in adults with cardiovascular risk factors; however, whether these improvements can be observed in at-risk adolescents is unknown. A randomised, double-blind, cross-over study enrolled twenty-five overweight or obese...

Resveratrol supplementation has been reported to improve markers of vascular function, but poor bioavailability of the parent compound is thought to limits its use. In this study, we compared the effects of a resveratrol-arginine conjugate (ResArg) to trans-resveratrol (trans-Res), the standard form used in supplements, on measures of microvascular...

Resveratrol supplementation has been reported to improve markers of vascular function, but poor bioavailability of the parent compound limits its use. In this study, we compared the effects of a resveratrol-arginine conjugate (ResArg) to trans-resveratrol (trans-Res), the standard form used in supplements, on measures of microvascular function 1 h...

Background:Maternal nutritional status can impact numerous early developmental processes.In certain cases,these effects can influence the risktheiroffspring can havefor select chronic diseases later in life. Consequently, in this article wereport on the effects of maternal consumption of high levels of certain flavonoids on the development of coron...

Previous studies have shown that the intake of freeze‐dried strawberry powder (FDSP) improves select markers of cardiovascular health in at risk individuals; whether these improvements can be observed in adolescents is unknown. A randomized, double‐blind, crossover study enrolled 25 overweight or obese males, ages 14–18 years, to consume 50g of FDS...

Reported dietary intake is often used in community interventions to assess intake of fruits and vegetables (F/V); however, dietary assessment methods are inaccurate, and time and labor intensive. Skin carotenoids are a potential biomarker to assess F/V intake given that carotenoids are predominately found in F/V and their concentration in the skin...

Maternal nutrition can have a significant effect on developmental processes during pregnancy and lactation. While certain flavonoids have been postulated to be beneficial for health, little is known about the effects of ingestion during pregnancy and lactation on the mother and progeny. We report on the effects of maternal consumption of high level...

Objective: This study investigated select vitamin and trace element loss from wound exudates in burn and trauma patients treated with negative-pressure wound therapy (NPWT). Design: A prospective observational study was performed using wound exudate samples. Setting: A level I trauma center acute care hospital. Participants: The study was co...

Vitamin D is well recognized for its essentiality in maintaining skeletal health. Recent research has suggested that vitamin D may exert a broad range of roles throughout the human life cycle starting from reproduction to adult chronic disease risk. Rates of vitamin D deficiency during pregnancy remain high worldwide. Vitamin D deficiency has been...

Background: Evidence from dietary intervention studies shows that the intake of flavanols and procyanidins can be beneficial for cardiovascular health. Nevertheless, there is a clear need for advancing our understanding with regard to safe amounts of intake for these bioactives. Objective: The aim was to investigate in healthy adults the effects...

The potential of micronutrients to ameliorate the impact of prenatal alcohol exposure (PAE) was explored in a clinical trial conducted in Ukraine. Cardiac orienting responses (ORs) during a habituation/dishabituation learning paradigm were obtained from 6 to 12 month-olds to assess neurophysiological encoding and memory. Women who differed in prena...

Fetal alcohol spectrum disorders are more common in disadvantaged populations. Environmental factors, like suboptimal nutrition, may potentiate the developmental effects of prenatal alcohol exposure. To evaluate the impact of micronutrients, including choline, on reduction of effects of exposure, we examined timing and dose of alcohol and effects o...

Elevated plasma IL-6 concentrations during pregnancy are associated with certain neurological disorders (e.g. autism and schizophrenia) in offspring. We investigated the hypothesis that IL-6 is a risk factor in women who gave birth to a child with FASD. Alcohol-exposed and control women were recruited during mid pregnancy (mean gestational age 20.4...

Background: Lipid mediators are transported in plasma, inducing pro- or anti-inflammatory responses in target tissues. Each daily nut serving is associated with 30% reduction in risk for cardiovascular or ischemic heart disease. Walnuts are an abundant source of bioactives and of precursors to lipid mediator synthesis: linoleic (LA) and alpha-linol...

Lipoproteins transport lipid mediators through the body, making them an important component of lipid mediator biology. Walnuts are an abundant dietary source of linoleic (LA) and alpha‐linolenic (aLA) acids. They also improve plasma lipoprotein profiles. Both are likely to impact the quality and quantity of lipoprotein lipid mediators. We measured...

Walnuts are a source of alpha‐linolenic acid (ALA) and linoleic acid (LA). We examined the effects of short‐term walnut intake on the reactive hyperemia index (RHI), a measure of microvascular function. We hypothesized that 4 weeks of 40g/day of walnuts would improve RHI compared to 5g/day of walnuts in hypercholesterolemic postmenopausal women. Mi...

Elevated plasma IL‐6 concentrations during pregnancy are associated with certain neurological disorders (e.g. autism and schizophrenia) in offspring. We investigated the hypothesis that IL‐6 is a risk factor in women who gave birth to a child with FASD. Alcohol‐exposed and control women were recruited during mid pregnancy (mean gestational age 20.4...

Objective: Normal iron handling appears to be disrupted in critically ill patients leading to hypoferremia that may contribute to systemic inflammation. Ceruloplasmin (Cp), an acute phase reactant protein that can convert ferrous iron to its less reactive ferric form facilitating binding to ferritin, has ferroxidase activity that is important to ir...

BACKGROUND Developmental zinc (Zn) deficiency increases the incidence of heart anomalies in rat fetuses, in regions and structures derived from the outflow tract. Given that the development of the outflow tract requires the presence of cardiac neural crest cells (cNCC), we speculated that Zn deficiency selectively kills cNCC and could lead to heart...

Fortification is the process of adding nutrients or non-nutrient bioactive components to edible products (e.g., food, food constituents, or supplements). Fortification can be used to correct or prevent widespread nutrient intake shortfalls and associated deficiencies, to balance the total nutrient profile of a diet, to restore nutrients lost in pro...

Objective: To provide a framework for implementation of multicomponent, school-based nutrition interventions. This article describes the research methods for the Shaping Healthy Choices Program, a model to improve nutrition and health-related knowledge and behaviors among school-aged children. Design: Longitudinal, pretest/posttest, randomized,...

Lyme disease was originally identified in Lyme, Connecticut, based upon an unusual cluster of what appeared to be patients with juvenile rheumatoid arthritis. It was subsequently identified as a new clinical entity originally called Lyme arthritis based on the observation that arthritis was a major clinical feature. However, Lyme arthritis is now c...

Previous studies in mice have shown that topical L-selenomethionine (SeMet) can prevent UVB-induced skin cancer when applied continuously before, during, and after the radiation exposure. With topical application of SeMet, selenium levels were shown to increase in the skin and liver, as well as in tumor tissue. Thus, possibly, the timing of SeMet a...

: Advances in nutrition during the past century have helped untold numbers of people around the world enjoy healthier and longer lives and be more productive members of society. These advances include the identification of numerous essential nutrients, the identification of common disease states that can arise as a consequence of deficiencies of th...

Background Wilson disease (WD) is characterized by hepatic copper accumulation with progressive liver damage to cirrhosis. This study aimed to characterize the toxic milk mouse from The Jackson Laboratory (Bar Harbor, ME, USA) (tx-j) mouse model of WD according to changes over time in hepatic copper concentrations, methionine metabolism, global DNA...

The Shaping Healthy Choices Program (SHCP) is a school‐based intervention that integrates 5 components: nutrition education; family and community partnerships; regional agriculture; foods available on school site; and school wellness policies. This study tests the hypothesis that schools using the SHCP during one school year will improve health‐rel...

We examined the relationship of walnut intake and walnut derived fatty acids on outcome measures of vascular health. Hypercholesterolemic postmenopausal women (n=36) were randomized to 4 weeks of 5 or 40g of daily walnut intake. Outcomes were measured after an overnight fast and 4 h after walnut intake, prior to and after the 4 week intervention. F...

Over 340,000 bariatric surgeries are performed annually worldwide, many of them on young individuals. While successful weight loss can occur, it has been associated with a number of nutritional deficiencies. In this prospective study, blood was taken from 21 female patients (19 White, 2 Black; age = 44.5 ± 2 yrs; body mass index (BMI) = 54.8 ± 1.7...

Genetic variations can affect how nutrients are metabolized, while nutrient deficiencies can have an effect on genetic variation. This article discusses the future challenges and present ethical considerations in the use of personalized nutrition based on genetic polymorphisms that increase an individual's risk for developing, or susceptibility to,...

The functions of vitamins and selected vitamin-like biofactors are summarized. Basic mechanisms of actions are described that are important to an understanding of the deficiency signs or symptoms that are observed when such compounds are limiting in the diet of animals. With respect to given biofactors, primary and secondary metabolites that are pr...

Maternal diet can affect fetal gene expression through epigenetic mechanisms. Wilson disease (WD), which is caused by autosomal recessive mutations in ATP7B encoding a biliary copper transporter, is characterized by excessive hepatic copper accumulation, but variability in disease severity. We tested the hypothesis that gestational supply of dietar...

The essentiality of zinc for normal brain development is well established. It has been suggested that primary and secondary zinc deficiencies can contribute to the occurrence of numerous human birth defects, including many involving the central nervous system. In a recent study, we searched for zinc transporter genes that were critical for neurodev...

Zn(2+) is required for many aspects of neuronal structure and function. However, the regulation of Zn(2+) in the nervous system remains poorly understood. Systematic analysis of tissue-profiling microarray data showed that the zinc transporter ZIP12 (slc39a12) is highly expressed in the human brain. In the work reported here, we confirmed that ZIP1...

The objective of this study is to evaluate the relationship between biomarkers of fruit and vegetable intake comparing plasma and dermal carotenoids to reported intake. It is important to have a valid, objective, and non‐invasive method to assess nutritional status in children and a feasible data collection method. As part of the multi‐component nu...

The Shaping Healthy Choices Program (SHCP) involves the integration of five components: nutrition education; family and community partnerships; regional agriculture; foods available on school site; and school wellness policies. This study uses a pre‐/post‐test design to test the hypothesis that schools utilizing the SHCP will improve nutrition know...

Walnuts contain a number of phenolic acids, polyphenols and lipids that may benefit cardiovascular health. We examined the effects of acute (4 hours) and short‐term (4 weeks) walnut intake on select cardiovascular outcome measures. Thirty‐six hypercholesterolemic postmenopausal women were randomly assigned to consume 5 or 40 g of walnuts daily for...

The essentiality of vitamin D for normal growth and development has been recognized for over 80 years, and vitamin D fortification programs have been in place in the United States for more than 70 years. Despite the above, vitamin D deficiency continues to be a common finding in certain population groups. Vitamin D deficiency has been suggested as...

In this study, the efficacy of orally and parenterally administered curcumin was evaluated in non‑obese diabetic̸severe combined immunodeficient (NOD/SCID) mice (NOD.CB17-Prkdcscid/J mice) engrafted with the human t(4;11) acute lymphoblastic leukemia line, SEM. SEM cells were injected into the tail vein and engraftment was monitored by flow cytomet...

Acute lymphoblastic leukemia (ALL) with translo-cation t(4;11) is a high-risk leukemia found in 60-85% of infants with ALL and is often refractory to conventional chemotherapeutics after relapse. To evaluate the efficacy of dietary resveratrol in vivo, 5-week-old NOD.CB17-Prkdcscid/J mice were fed a control diet or a diet containing 0.2% w/w resver...

Advancing age is an independent major risk factor for cardiovascular disease (CVD). Age-associated impairments in the control of inflammation, excessive oxidative stress, and reduced cellular repair can all contribute to the development and progression of CVD. Current recommendations for both the primary and secondary prevention of CVD promote life...