This Week in Science for Holistic Health
Welcome to This Week in Science for Holistic Health!
Weekly science news to keep holistic health professionals up-to-date with current research.
Foods, Diets & Eating – We are still looking at effects of foods on our gut microbiota
Supplements & Nutrients – More evidence needed for probiotics for IBS
Lifestyle – Can we predict sedentary behaviour in children?
Anatomy & Physiology – We don’t really know the full effects of human milk on infants’ microbiome
Foods, Diets & Eating
Diet has been shown to be a major factor in modulating the structure of the mammalian gut microbiota by providing specific nutrient sources and inducing environmental changes (pH, bile acids) in the gut ecosystem. Long-term dietary patterns and short-term interventions have been shown to induce changes in gut microbiota structure and function, with several studies revealing metabolic changes likely resulting from the host-microbiota cross-talk, which ultimately could influence host physiology. However, a more precise identification of the specific dietary patterns and food constituents that effectively modulates the gut microbiota and brings a predictable benefit to the host metabolic phenotype is needed to establish microbiome-based dietary recommendations. Here we briefly review the existing data regarding gut microbiota changes induced by different macronutrients and the resulting metabolites produced via their respective fermentation, including their potential effects on obesity and associated metabolic disorders. We also discuss major limitations of current dietary intervention studies as well as future needs of applying cutting-edge ‘omic’ techniques and of progressing in functional microbiota gene discovery to establish robust causal relationships between the dietary-microbiota-induced changes and metabolic health or disease
A Daily Snack Containing Leafy Green Vegetables, Fruit, and Milk Before and during Pregnancy Prevents Gestational Diabetes in a Randomized, Controlled Trial in Mumbai, India.
BACKGROUND: Prospective observational studies suggest that maternal diets rich in leafy green vegetables and fruit may help prevent gestational diabetes mellitus (GDM).
OBJECTIVE: Our objective was to test whether increasing women’s dietary intake of leafy green vegetables, fruit, and milk before conception and throughout pregnancy reduced their risk of GDM.
CONCLUSIONS: In low-income settings, in which women have a low intake of micronutrient-rich foods, improving dietary micronutrient quality by increasing intake of leafy green vegetables, fruit, and/or milk may have an important protective effect against the development of GDM. This trial was registered at www.controlled-trials.com as ISRCTN62811278.
The relationship between diet and acne is highly controversial. Several studies during the last decade have led dermatologists to reflect on a potential link between diet and acne. This article presents the latest findings on a potential impact that diet can have on pathogenesis of acne vulgaris. The association between diet and acne can no longer be dismissed. Compelling evidence shows that high glycemic load diets may exacerbate acne. Dairy ingestion appears to be weakly associated with acne and the roles of omega-3 fatty acids, dietary fiber, antioxidants, vitamin A, zinc and iodine remain to be elucidated. The question of what the impact of diet is on the course of acne vulgaris still remains unclear.
INTRODUCTION: Cancer is a complex disease involving neoplasm of abnormal cells leading to development of tumor cells. Gene mutations result in aberrant gene expression, which is the major cause observed in all the cancers. The GLOBOCAN 2012 reported the highest age-standardized rates for cancer of the colorectum followed by stomach, liver, and esophagus, which are gastrointestinal cancers, and the new cases also followed the same order across the globe. Various risk factors are associated with different types of cancer which can be classified as dietary and non-dietary risk factors. The dietary risk factors include diet, alcohol, and nutrient deficiencies, whereas the non-dietary risk factors of cancers are tobacco, lifestyle choices, certain infections, occupational exposures, and environmental factors.
PURPOSE: The aim of this review is to focus on the dietary and non-dietary risk factors linked to gastrointestinal cancers, which could be beneficial in clinical decision-making.
OBJECTIVE: To conduct a comprehensive literature review in the field of added-sugar consumption on weight gain including the effect of fructose-containing caloric sweeteners and sugar taxation.
METHODS: A search of three databases was conducted in the time period from the inception of the databases to August 2015. Sensitive search strategies were used in order to retrieve systematic reviews (SR) of fructose, sucrose, or sugar-sweetened beverages (SSBs) on weight gain and metabolic adverse effects, conducted on humans and written in English, Spanish, or French. In addition, a review about SSB taxation and weight outcomes was conducted.
RESULTS: The search yielded 24 SRs about SSBs and obesity, 23 SRs on fructose or SSBs and metabolic adverse effects, and 24 studies about SSB taxation and weight control.
CONCLUSIONS: The majority of SRs, especially the most recent ones, with the highest quality and without any disclosed conflict of interest, suggested that the consumption of SSBs is a risk factor for obesity. The effect of fructose-containing caloric sweeteners, on weight gain is mediated by overconsumption of beverages with these sweeteners, leading to an extra provision of energy intake. The tax tool alone on added sugars appears insufficient to curb the obesity epidemic, but it needs to be included in a multicomponent structural strategy.
Supplements & Nutrients
British Dietetic Association systematic review of systematic reviews and evidence-based practice guidelines for the use of probiotics in the management of irritable bowel syndrome in adults (2016 update).
BACKGROUND: Probiotics are often taken by individuals with irritable bowel syndrome (IBS). Which products are effective is unclear, despite an increasing research base. This project will systematically review which strain- and dose- specific probiotics can be recommended to adults with IBS to improve symptoms and quality of life (QoL). It is part of a broader systematic review to update British Dietetic Association guidelines for the dietary management of IBS in adults.
RESULTS: Nine systematic reviews and 35 RCTs were included (3406 participants) using 29 dose-specific probiotic formulations. None of the RCTs were at low risk of bias. Twelve out of 29 probiotics (41%) showed no symptom or QoL benefits. Evidence indicated that no strain or dose specific probiotic was consistently effective to improve any IBS symptoms or QoL. Two general clinical practice recommendations were made.
CONCLUSIONS: Symptom outcomes for dose-specific probiotics were heterogeneous. Specific probiotic recommendations for IBS management in adults were not possible at this time. More data from high-quality RCTs treating specific symptom profiles are needed to support probiotic therapy in the management of IBS.
Neither Preconceptional Weekly Multiple Micronutrient nor Iron-Folic Acid Supplements Affect Birth Size and Gestational Age Compared with a Folic Acid Supplement Alone in Rural Vietnamese Women: A Randomized Controlled Trial.
BACKGROUND: Maternal nutritional status before and during early pregnancy plays a critical role in fetal growth and development. The benefits of periconception folic acid (FA) supplementation in the prevention of neural tube defects is well recognized, but the evidence for preconception micronutrient interventions for improving pregnancy outcomes is limited.
OBJECTIVE: This study aimed to evaluate whether preconception supplementation with weekly iron and folic acid (IFA) or multiple micronutrients (MMs) improves birth outcomes compared with FA alone.
CONCLUSION: Weekly supplementation with MMs or IFA before conception did not affect birth outcomes compared with FA in rural Vietnamese women. The trial was registered at clinicaltrials.gov as NCT01665378.
Fortification of staple foods with zinc for improving zinc status and other health outcomes in the general population.
Background – It is believed that zinc deficiency is widespread globally, particularly in children and women living in low- and middle-income countries. Cereal-based foods are rich in dietary fibre and phytates, which reduce absorption of zinc from the intestine. As people in low-income households eat a lot of cereal-based foods, they are more likely to develop zinc deficiency. Fortification of common staple foods with zinc alone or in combination with other vitamins and minerals has been proposed as an intervention to increase intake of zinc in populations who consume these foods.
Review question – We evaluated the effects of fortification of staple foods with zinc on blood zinc levels and health-related outcomes in the general population above two years of age.
Study characteristics – We included eight trials (709 participants); seven were from middle-income countries of Asia, Africa, Europe, and Latin America where zinc deficiency is likely to be a public health problem.
Key results and quality of the evidence – The effect of fortification of foods with zinc on incidence of zinc deficiency is uncertain. Fortification of foods with zinc may slightly improve the blood zinc levels of populations if zinc is the only micronutrient used for fortification. Zinc added to food in combination with other micronutrients may make little or no difference to blood zinc levels. The fortification of foods with zinc may make little or no difference on incidence of underweight or stunting. The effects of fortification of foods with zinc on other outcomes, including wasting and weight/height, are unknown. Fortification of foods with zinc does not seem to have any adverse effect on indicators of iron or copper status. Most studies included in this review involved a small number of participants and were judged to be at low or unclear risk of bias. There were also some inconsistencies in the results across different studies.
• Manganese is an essential trace element that is abundant in plant-based foods.
• The majority of dietary standards are based on adequate intakes derived from usual diets.
• International variability in dietary Mn is substantial due to food and culture diversity.
• With the nutrition transition, diets have shifted to processed foods that are low in Mn.
Manganese (Mn) is an essential trace element that is critical for human health and development. At the turn of the century when diets were based on whole grains, cereals and other traditional foods, Mn intakes (8-9mg/d) were much greater than that prevalent today (2mg/d). As societies have developed, diets have shifted as part of a nutrition transition, to those that are high in processed foods, fat, and sugar. These foods are virtually devoid of Mn. Thus, dietary Mn has declined substantially throughout the world, as confirmed by several wide-scale, total diet studies. International variability in dietary Mn is considerable, due to tremendous diversity in food and culture. In countries where fruit and vegetable intake may be limited, i.e. the United Kingdom, populations may ingest much lower levels of Mn (1.4mg/d) as compared to Asian cultures (4mg/d) which have an abundance of plant foods in their food supply and cuisine. The bioavailability of Mn must be considered, including chemical form, oxidation state, mineral-mineral interactions, presence of dietary components and traditional food processing techniques (milling, germination, malting, fermentation). Manganese toxicity is a public health problem that results from exposure to a naturally high water source or contaminated environment of the soil and/or drinking water. In contrast, inadequate intake is associated with adverse health effects such as diabetes, metabolic syndrome, poor birth outcomes and possibly, cancer. Future studies are recommended to set dietary standards for this mineral in countries that lack recommendations to help achieve optimal health.
Melanoma remains among the most lethal cancers and, in spite of great attempts that have been made to increase the life span of patients with metastatic disease, durable and complete remissions are rare. Plants and plant extracts have long been used to treat a variety of human conditions; however, in many cases, effective doses of herbal remedies are associated with serious adverse effects. Curcumin is a natural polyphenol that shows a variety of pharmacological activities including anti-cancer effects, and only minimal adverse effects have been reported for this phytochemical. The anti-cancer effects of curcumin are the result of its anti-angiogenic, pro-apoptotic, and immunomodulatory properties. At the molecular and cellular level, curcumin can blunt epithelial-to-mesenchymal transition and affect many targets that are involved in melanoma initiation and progression (e.g. BCl2, MAPKS, p21 and some microRNAs). However, curcumin has a low oral bioavailability that may limit its maximal benefits. The emergence of tailored formulations of curcumin and new delivery systems such as nanoparticles, liposomes, micelles and phospholipid complexes has led to the enhancement of curcumin bioavailability. Although in vitro and in vivo studies have demonstrated that curcumin and its analogues can be used as novel therapeutic agents in melanoma, curcumin has not yet been tested against melanoma in clinical practice. In this review, we summarized reported anti-melanoma effects of curcumin as well as studies on new curcumin formulations and delivery systems that show increased bioavailability. Such tailored delivery systems could pave the way for enhancement of the anti-melanoma effects of curcumin.
NOTE from Leesa: If you have experienced an adverse event related to your use of any supplement or medication, AND you’re in Canada or the USA, you can report them directly to the health authorities at the links below. Health Canada’s MedEffect link is reference (3), and the FDA’s MedWatch link is reference (4).
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Prenatal, birth and early life predictors of sedentary behavior in young people: a systematic review.
BACKGROUND: Our aim was to systematically summarize the evidence on whether prenatal, birth and early life factors up to 6 years of age predict sedentary behavior in young people (≤18 years).
RESULTS: More than 18,000 articles were screened, and 16 studies, examining 10 different predictors, were included. Study quality was variable (0.36-0.95). Two studies suggest that heritability and BMI in children aged 2-6 years were significant predictors of sedentary behavior later in life, while four and seven studies suggest no evidence for an association between gestational age, birth weight and sedentary behavior respectively. There was insufficient evidence whether other prenatal, birth and early life factors act as predictors of later sedentary behavior in young people.
CONCLUSION: The results suggest that heritability and early childhood BMI may predict sedentary behavior in young people. However, small number of studies included and methodological limitations, including subjective and poorly validated sedentary behavior assessment, limits the conclusions.
Anatomy & Physiology
Beyond its nutritional aspects, human milk contains several bioactive compounds, such as microbes, oligosaccharides, and other substances, which are involved in host-microbe interactions and have a key role in infant health. New techniques have increased our understanding of milk microbiota composition, but few data on the activity of bioactive compounds and their biological role in infants are available. Whereas the human milk microbiome may be influenced by specific factors – including genetics, maternal health and nutrition, mode of delivery, breastfeeding, lactation stage, and geographic location – the impact of these factors on the infant microbiome is not yet known. This article gives an overview of milk microbiota composition and activity, including factors influencing microbial composition and their potential biological relevance on infants’ future health.
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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 is a science-based holistic nutritionist living 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 MSc in Toxicology and Nutritional Science, over a decade experience in drug/supplement safety, and is also a Registered Holistic Nutritionist. For a list of free health resources, click here.
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