This Week in Science for Holistic Health
Welcome to This Week in Science for Holistic Health!
I scour the science news for interesting and relevant research for a holistic approach to health.
Food and Eating – Is fat the sixth taste modality?
Supplements and Herbs – Benefits of iron supps and vit D supps, but not multi’s.
Disease Prevention – Diet and lifestyle for infertility?
Anatomy & Physiology – More evidence that antioxidants aren’t always beneficial.
Food and Eating
It is Rocket Science – Why dietary nitrate is hard to beet! Part I: Twists and turns in the realisation of the nitrate-nitrite-NO pathway.
Dietary nitrate (found in green leafy vegetables such as rocket and in beetroot) is now recognised to be an important source of nitric oxide, via the nitrate-nitrite-NO pathway. Dietary nitrate confers several cardiovascular beneficial effects on blood pressure, platelets, endothelial function, mitochondrial efficiency and exercise. Whilst this pathway may now seem obvious, its realisation followed a rather tortuous course over two decades. Early steps included the discovery that nitrite was a source of NO in the ischaemic heart, but this appeared to have deleterious effects. In addition, nitrate-derived nitrite provided a gastric source of NO. However, residual nitrite was not thought to be absorbed systemically. Nitrite was also considered to be physiologically inert, but potentially carcinogenic, through N-nitrosamine formation. In Part I we describe key twists and turns in the elucidation of the pathway and the underlying mechanisms. This provides the critical foundation for the more recent developments in the nitrate-nitrite-NO pathway which are covered in Part II.
Is Higher Consumption of Animal Flesh Foods Associated with Better Iron Status among Adults in Developed Countries? A Systematic Review.
Iron deficiency (ID) is the most prevalent nutrient deficiency within the developed world. This is of concern as ID has been shown to affect immunity, thermoregulation, work performance and cognition. Animal flesh foods provide the richest and most bioavailable source of dietary (haem) iron, however, it is unclear whether low animal flesh diets contribute to ID. This systematic review aimed to investigate whether a higher consumption of animal flesh foods is associated with better iron status in adults. CINAHL, Cochrane, EMBASE and MEDLINE were searched for published studies that included adults (≥18 years) from developed countries and measured flesh intakes in relation to iron status indices. Eight experimental and 41 observational studies met the inclusion criteria. Generally, studies varied in population and study designs and results were conflicting. Of the seven high quality studies, five showed a positive association between animal flesh intake (85-300 g/day) and iron status. However, the optimum quantity or frequency of flesh intake required to maintain or achieve a healthy iron status remains unclear. Results show a promising relationship between animal flesh intake and iron status, however, additional longitudinal and experimental studies are required to confirm this relationship and determine optimal intakes to reduce ID development.
An attraction for palatable foods rich in lipids is shared by rodents and humans. Over the last decade, the mechanisms responsible for this specific eating behavior have been actively studied, and compelling evidence implicates a taste component in the orosensory detection of dietary lipids [i.e., long-chain fatty acids (LCFA)], in addition to textural, olfactory, and postingestive cues. The interactions between LCFA and specific receptors in taste bud cells (TBC) elicit physiological changes that affect both food intake and digestive functions. After a short overview of the gustatory pathway, this review brings together the key findings consistent with the existence of a sixth taste modality devoted to the perception of lipids. The main steps leading to this new paradigm (i.e., chemoreception of LCFA in TBC, cell signaling cascade, transfer of lipid signals throughout the gustatory nervous pathway, and their physiological consequences) will be critically analyzed. The limitations to this concept will also be discussed in the light of our current knowledge of the sense of taste. Finally, we will analyze the recent literature on obesity-related dysfunctions in the orosensory detection of lipids (“fatty” taste?), in relation to the overconsumption of fat-rich foods and the associated health risks.
Centella asiatica L. (Gotu Kola) is a nutritionally important plant and a valued traditional medicine in South East Asia. In this review, the chemical composition, nutritional values, and health benefits of C. asiatica have been discussed in detail to emphasize its usage as traditional food and medicine. C. asiatica is one of the most commonly used green leafy vegetables (GLVs) in some countries including Sri Lanka due to its high amounts of medicinally important triterpenoids and beneficial carotenoids. It is consumed in the form of GLVs and in the preparation of juice, drink, and other food products. It is also known to contain vitamins B and C, proteins, important minerals, and some other phytonutrients such as flavonoids, volatile oils, tannins, and polyphenol. In vitro and in vivo studies have shown important health benefits like antidiabetic, wound-healing, antimicrobial, memory-enhancing, antioxidant, and neuroprotecting activities. However, detailed scientific approaches on clinical trials regarding health benefits and nutritional values of C. asiatica are limited, hindering the perception of its benefits, mechanisms, and toxicity in order to develop new drug prototypes. In vitro studies have shown that the method of processing C. asiatica has an impact on its nutritional values and health-related beneficial compounds. The composition of its compounds is influenced by different biotic and abiotic factors which need to be studied in detail to provide information to the public in order to maximize the usage of this valuable plant.
Supplements and Herbs
Oral Iron for Anemia: A Review of the Clinical Effectiveness, Cost-effectiveness and Guidelines [Internet].
Oraliron salts such as ferrous fumarate, ferrous gluconate, and ferrous sulfate have been the mainstay of oral iron supplementation because they are inexpensive, effective at restoring iron balance, and have good overall safety and tolerability profile. However, in some patients, absorption of oral iron salts is inadequate, and poor tolerance results in reduced adherence to therapy. Polysaccharide iron complex and heme iron polypeptide products have become available as alternative therapies, offering improved absorption and tolerability profile over the traditional iron salts. However, they are significantly more expensive than iron salts. The aim of this review is to summarize current evidence on the comparative clinical and cost effectiveness of oral and injectable iron supplementation products for iron deficiency anemia (IDA).
Overall, oral HIP (heme iron polypeptide) and oral IPC (iron polymaltose complex) preparations did not appear to confer superior efficacy benefit over traditional oral iron salt or intravenous iron supplementation for the treatment of iron deficiency anemia. Although one RCT5 reported that oral IPC had a superior safety profile compared to ferrous sulfate for the treatment of iron-deficiency anemia during pregnancy, both interventions were well tolerated by the patients, with no serious adverse events occurring in either treatment group.
- Looks like most iron supps, whether they’re iron salts or newer (and more expensive) polypeptide/polysaccharide complexes work to treat iron-deficiency anemia, they’re well tolerated with no serious adverse events.
BACKGROUND: Vitamin D deficiency is highly prevalent during pregnancy. It has been suggested that vitamin D supplementation during pregnancy may reduce the risk of adverse gestational outcomes.
OBJECTIVES: To update a previous meta-analysis on the effects of oral vitamin D supplementation (alone or in combination with other vitamins and minerals) during pregnancy on maternal 25(OH)D levels and risk of developing pre-eclampsia, gestational diabetes, preterm birth, impaired glucose tolerance, caesarean section, gestational hypertension and other adverse conditions.
CONCLUSION: Supplementing pregnant women with vitamin D led to significantly higher levels of 25(OH)D at term compared to placebo/control but results were inconsistent. Vitamin D supplementation, with or without calcium, may be related to lower risk of preeclampsia but more studies are needed to confirm this.
Supplementation with multiple micronutrients for breastfeeding women for improving outcomes for the mother and baby.
AUTHORS’ CONCLUSIONS: We found no evidence to quantitatively assess the effectiveness of multiple-micronutrient supplementation in improving health outcomes in mother and baby. The results of this review are limited by the small numbers of studies available, small sample sizes and the studies not reporting on the outcomes of interest in this review. There is no evidence to evaluate potential adverse effects of multiple-micronutrient supplements, particularly excess dosages.There is a need for high-quality studies to assess the effectiveness and safety of multiple-micronutrient supplementation for breastfeeding women for improving outcomes for the mother and her baby. Further research should focus on whether multiple-micronutrient supplementation during lactation compared with none, a placebo or supplementation with fewer than two micronutrients is beneficial to maternal and infant health outcomes. Future studies should collect data on outcomes beyond micronutrient concentrations, for example: maternal and infant morbidity, adverse effects, maternal satisfaction, the risks of excess supplementation, and potential adverse interactions between the micronutrients and the other outcomes. This would help to bridge the gap between research on intermediary outcomes and health outcomes in order to develop sound policy in this field. Future studies could more precisely assess a variety of multiple-micronutrient combinations and different dosages and look at how these affect maternal and infant health outcomes. Larger studies with longer follow-up would improve the quality of studies and provide stronger evidence. In most of the included studies, bias could not be adequately assessed due to lack of information, therefore attention should be given to adequate methods of randomisation and allocation concealment, adequate methods of blinding of the participants, providers and the outcome assessors to improve the methodological quality of studies in this field.
- There does not seem to be much evidence of benefit of multi-vitamin/mineral supplementation for breastfeeding women or their babies.
Nigella Sativa (Black Seed) Effects on Plasma Lipid Concentrations in Humans: a Systematic Review and Meta-Analysis of Randomized Placebo-Controlled Trials.
… NS has a significant impact on plasma lipid concentrations, leading to lower total cholesterol, LDL-C, and TG levels while increased HDL-C is associated with NS powder only. Further RCTs are needed to explore the NS benefits on cardiovascular outcomes.
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Diseases/Conditions and Prevention/Treatments
The impact of nutrients on the aging rate: a complex interaction of demographic, environmental and genetic factors.
Nutrition has a strong influence on the health status of the elderly, with many dietary components associated to either an increased risk of disease or to an improvement of the quality of life and to a delay of age-related pathologies. A direct effect of a reduced caloric intake on the delay of aging phenotypes is documented in several organisms. The role of nutrients in the regulation of human lifespan is not easy to disentangle, influenced by a complex interaction of nutrition with environmental and genetic factors. The individual genetic background is fundamental for mediating the effects of nutritional components on aging. Classical genetic factors able to influence nutrient metabolism are considered those belonging to insulin/insulin growth factor (INS/IGF-1) signaling, TOR signaling and Sirtuins, but also genes involved in inflammatory/immune response and antioxidant activity can have a major role. Considering the worldwide increasing interest in nutrition to prevent age related diseases and achieve a healthy aging, in this review we will discuss this complex interaction, in the light of metabolic changes occurring with aging, with the aim of shedding a light on the enormous complexity of the metabolic scenario underlying longevity phenotype.
- Aging is complex! Influenced by the diet, caloric intake, nutrients, genes and other factors. 🙂
The Deep Correlation between Energy Metabolism and Reproduction: A View on the Effects of Nutrition for Women Fertility.
In female mammals, mechanisms have been developed, throughout evolution, to integrate environmental, nutritional and hormonal cues in order to guarantee reproduction in favorable energetic conditions and to inhibit it in case of food scarcity. This metabolic strategy could be an advantage in nutritionally poor environments, but nowadays is affecting women’s health. The unlimited availability of nutrients, in association with reduced energy expenditure, leads to alterations in many metabolic pathways and to impairments in the finely tuned inter-relation between energy metabolism and reproduction, thereby affecting female fertility. Many energetic states could influence female reproductive health being under- and over-weight, obesity and strenuous physical activity are all conditions that alter the profiles of specific hormones, such as insulin and adipokines, thus impairing women fertility. Furthermore, specific classes of nutrients might affect female fertility by acting on particular signaling pathways. Dietary fatty acids, carbohydrates, proteins and food-associated components (such as endocrine disruptors) have per se physiological activities and their unbalanced intake, both in quantitative and qualitative terms, might impair metabolic homeostasis and fertility in premenopausal women. Even though we are far from identifying a “fertility diet”, lifestyle and dietary interventions might represent a promising and invaluable strategy to manage infertility in premenopausal women.
Nevertheless, nutrition and lifestyle changes are still one of the most promising and invaluable interventions in preserving human health and women fertility and represent the most captivating challenge that we also have to take up today as Hippocrates, in the 4th century BC, suggested:
“If we could give every individual the right amount of nourishment and exercise, not too little and not too much, we would have found the safest way to health”.
- Diet and lifestyle changes may help manage infertility in women, but we don’t have enough information to create a full strategy yet.
Following the epidemics of obesity, nonalcoholic fatty liver disease (NAFLD) has become the leading cause of liver disease in western countries. NAFLD is the hepatic manifestation of metabolic syndrome and may progress to cirrhosis and hepatocellular carcinoma. To date, there are no approved drugs for the treatment of NAFLD, and the main clinical recommendation is lifestyle modification, including increase of physical activity and the adoption of a healthy eating behavior. In this regard, studies aimed to elucidate the effect of dietary interventions and the mechanisms of action of specific food bioactives are urgently needed. The present review tries to summarize the most recent data evidencing the effects of nutrients and dietary bioactive compounds intake (i.e., long-chain PUFA, Vitamin E, Vitamin D, minerals and polyphenols) on the modulation of molecular mechanisms leading to fat accumulation, oxidative stress, inflammation and liver fibrosis in NAFLD patients.
- Evidence that long-chain PUFAs, vitamins D & E, minerals and polyphenols may help with non-alcoholic fatty liver disease.
As with physical conditions, bipolar disorder is likely to be impacted by diet and nutrition. Patients with bipolar disorder have been noted to have relatively unhealthy diets, which may in part be the reason they also have an elevated risk of metabolic syndrome and obesity. An improvement in the quality of the diet should improve a bipolar patient’s overall health risk profile, but it may also improve their psychiatric outcomes. New insights into biological dysfunctions that may be present in bipolar disorder have presented new theoretic frameworks for understanding the relationship between diet and bipolar disorder.
- We are just learning the relationship between diet and bipolar disorder.
Lifestyle Interventions to Prevent Type 2 Diabetes: A Systematic Review of Economic Evaluation Studies.
Objective. To summarize key findings of economic evaluations of lifestyle interventions for the primary prevention of type 2 diabetes (T2D) in high-risk subjects. Methods. We conducted a systematic review of peer-reviewed original studies published since January 2009 in English, French, and Spanish. Eligible studies were identified through relevant databases including PubMed, Medline, National Health Services Economic Evaluation, CINHAL, EconLit, Web of sciences, EMBASE, and the Latin American and Caribbean Health Sciences Literature. Studies targeting obesity were also included. Data were extracted using a standardized method. The BMJ checklist was used to assess study quality. The heterogeneity of lifestyle interventions precluded a meta-analysis. Results. Overall, 20 studies were retained, including six focusing on obesity control. Seven were conducted within trials and 13 using modeling techniques. T2D prevention by physical activity or diet or both proved cost-effective according to accepted thresholds, except for five inconclusive studies, three on diabetes prevention and two on obesity control. Most studies exhibited limitations in reporting results, primarily with regard to generalizability and justification of selected sensitivity parameters. Conclusion. This confirms that lifestyle interventions for the primary prevention of diabetes are cost-effective. Such interventions should be further promoted as sound investment in the fight against diabetes.
- Proof that diet and exercise interventions can prevent type 2 diabetes.
Anatomy & Physiology
Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are generated from aerobic metabolism, as a result of accidental electron leakage as well as regulated enzymatic processes. Because ROS/RNS can induce oxidative injury and act in redox signaling, enzymes metabolizing them will inherently promote either health or disease, depending on the physiological context. It is thus misleading to consider conventionally called antioxidant enzymes to be largely, if not exclusively, health protective. Because such a notion is nonetheless common, we herein attempt to rationalize why this simplistic view should be avoided. First we give an updated summary of physiological phenotypes triggered in mouse models of overexpression or knockout of major antioxidant enzymes. Subsequently, we focus on a series of striking cases that demonstrate “paradoxical” outcomes, i.e., increased fitness upon deletion of antioxidant enzymes or disease triggered by their overexpression. We elaborate mechanisms by which these phenotypes are mediated via chemical, biological, and metabolic interactions of the antioxidant enzymes with their substrates, downstream events, and cellular context. Furthermore, we propose that novel treatments of antioxidant enzyme-related human diseases may be enabled by deliberate targeting of dual roles of the pertaining enzymes. We also discuss the potential of “antioxidant” nutrients and phytochemicals, via regulating the expression or function of antioxidant enzymes, in preventing, treating, or aggravating chronic diseases. We conclude that “paradoxical” roles of antioxidant enzymes in physiology, health, and disease derive from sophisticated molecular mechanisms of redox biology and metabolic homeostasis. Simply viewing antioxidant enzymes as always being beneficial is not only conceptually misleading but also clinically hazardous if such notions underpin medical treatment protocols based on modulation of redox pathways.
- More evidence that “antioxidants” does not always equal “good for you”.
Perinatal overweight and obesity is a major public health and clinical care issue that requires deliberate and immediate attention. Preconception and prenatal assessment and counseling should address the risks associated with obesity, recommendations for weight gain, proper nutrition and dietary intake, and physical activity. Nutrition and exercise guidance should be offered to all perinatal overweight and obese women with an emphasis on effective strategies to overcome barriers. All women should be encouraged to adopt a healthy lifestyle and achieve a healthy weight before becoming pregnant.
The National Health and Nutrition Examination Survey from the Centers for Disease Control and Prevention reports a steady increase in obesity over the last 30 years. The greatest increase was seen in 15 to 19 year olds, whose obesity prevalence almost doubled from 10.5% to 19.4%. The solution to pediatric obesity requires a multidisciplinary approach addressing cultural norms, technologic advances, and family engagement. Future treatment strategies to combat the obesity epidemic will have to extend beyond the health care provider’s office. Behavior modification remains the key component to pediatric obesity prevention and treatment.
Strategies to promote adherence to nutritional advice in patients with chronic kidney disease: a narrative review and commentary.
Chronic kidney disease (CKD) requires extensive changes to food and lifestyle. Poor adherence to diet, medications, and treatments has been estimated to vary between 20% and 70%, which in turn can contribute to increased mortality and morbidity. Delivering effective nutritional advice in patients with CKD coordinates multiple diet components including calories, protein, sodium, potassium, calcium, phosphorus, and fluid. Dietary intake studies have shown difficulty in adhering to the scope and complexity of the CKD diet parameters. No single educational or clinical strategy has been shown to be consistently effective across CKD populations. Highest adherence has been observed when both diet and education efforts are individualized to each patient and adapted over time to changing lifestyle and CKD variables. This narrative review and commentary summarizes nutrition education literature and published strategies for providing nutritional advice in CKD. A cohort of practical and effective strategies for increasing dietary adherence to nutritional advice are provided that include communicating with “talking control” principles, integrating patient-owned technology, acknowledging the typical food pattern may be snacking rather than formal meals, focusing on a single goal rather than multiple goals, creating active learning and coping strategies (frozen sandwiches, visual hands-on activities, planting herb gardens), and involving the total patient food environment.
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Inclusion Criteria for This Week in Science for Holistic Health posts:
- Studies must be published in a peer-reviewed medical journal or highly credible website (e.g. Cochrane.org) within the last few weeks,
- Articles must be relevant to a holistic approach to health (specifically nutrition & lifestyle factors),
- Studies were done on people unless noted otherwise (animal and tissue studies have unknown relevance to people),
- I also include new science-based books that look interesting (’cause I LOVE reading!).
- None of the above applies if it’s a response to something in the media. 😉
- P.S. – The titles are hyperlinked to the actual studies, so feel free to “geek out”. 🙂
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Leesa Klich lives at the intersection of science and holistic health (it’s really, really interesting here!) 🙂 At NutritionInteractions she helps holistic-minded people taking medications maximize the benefits of good nutrition. She also helps holistic health professionals find and understand science-based health information. She has a Master of Science degree in Toxicology and Nutrition and is currently studying to be a Registered Holistic Nutritionist. For a list of free health resources, click here.
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