Trending Topics pieces (Article Analyses, Evidence Clips and Other Topics) are published in timely response to recent media and journal articles, position statements, clinical guidelines, etc. Since they are based on the most recent evidence/publications, they may not be consistent with PEN evidence in other PEN content areas. As soon as possible, when this occurs, the PEN content will be reviewed and updated as needed.
Introduction of Allergenic Food to Infants, Especially Peanuts: Interim Guidelines for Canadian Dietitians
This interim DC communication provides DC members with information on the scientific evidence regarding the introduction of peanuts to infants and how the current dietetic practice recommendations agree and differ from NIAID recommendations published in January 2017. In brief, the key differences between these new NIAID guidelines and current Canadian Nutrition for Healthy Term Infant (NHTI) recommendations are in the different definitions of “at risk” infants, the strength of wording for introducing peanut containing food early, and the recommendation to undergo physician supervised testing/feeding before introduction for a small subset of very high-risk infants . Refer to the full document for more information. See also the PEN Evidence Clip : Food Allergy Prevention in Infants.
Plant-based Diet for the Management of Type 2 Diabetes
A review of the literature was conducted on the use of a plant-based diet in the management of type 2 diabetes as recommended by the Canadian Diabetes Association (1). Thirteen studies met the inclusion criteria. The authors defined a plant-based diet as: “a regimen that encourages whole, plant-based foods and discourages meats, dairy products and eggs as well as all refined and processed foods”. In observational studies the consumption of a plant-based diet was associated with decreased prevalence of type 2 diabetes. The observational studies may be limited in accuracy since people on plant-based diets tend to be more physically active, have more education, and have lower BMIs, which could account for some or all of the differences in diabetes prevalence. In addition, intervention studies indicate that a plant-based diet is equal to, or more effective than, other diets in managing type 2 diabetes. Plant-based diets were associated with improving body weight, cardiovascular risk factors and insulin sensitivity. Two of the five intervention studies recommended lower glycemic load foods only for their plant-based diet intervention groups, which may have contributed to the positive findings. It is not clear whether the benefits seen in the intervention studies were due to a lower consumption of meat and animal products and/or refined and processed foods or due to an increased consumption of vegetables. Recommendations are included in the paper for increasing client's acceptability and implementation of plant-based diets along with ways to enhance the capacity of health professionals to support the adoption of plant-based diets by individuals with type 2 diabetes.
Coincidentally, the American Academy of Nutrition and Dietetics recently published a position paper on vegetarian diets that also supports plant-based diets for better glycemic control in type 2 diabetes (2).
For your clients, see the new handout on PEN: Plant-based Diet Guidelines
- Rinaldi S, Campbell EE, Fournier J, O'Connor C, Madill J. A comprehensive review of the literature supporting recommendations from the Canadian Diabetes Association for the use of a plant-based diet for management of type 2 diabetes. Can J Diabetes. 2016 Oct;40(5):471-7. doi: 10.1016/j.jcjd.2016.02.011. Epub 2016 Jul 28. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/27476051
Kombucha Tea - Some Pros and Cons
Kombucha tea is a fermented drink made with sugar, tea, yeast and bacteria (1,2). It has been widely consumed around the world and there has been an increasing interest in drinking kombucha tea due to it being a probiotic beverage and its claimed potential health benefits. It is available commercially but is often prepared at home by combining the kombucha culture with sugared tea and allowing it to ferment. The composition of kombucha tea can vary depending on the starter tea, yeasts and bacteria contained in the culture, and the fermentation process.
A review in Comprehensive Reviews in Food Science and Food Safety provides an overview of the microbiology, composition, fermentation and potential benefits found in the literature up to 2013 (1). The authors noted that the biological effects underpinning the many health claims specific to kombucha consumption; notably antimicrobial, antioxidant, hepatoprotective and anticancer properties; have only been studied in animal and cell cultures. The authors concluded that kombucha tea can be part of a healthy diet, but more research is needed to determine its biological effects on humans.
There are some safety issues, mostly associated with non-commercially prepared kombucha. According to the Natural Medicines Comprehensive Database, kombucha tea when made in unhygienic conditions has been implicated in some cases of transmitted opportunistic pathogens and Aspergillus mould (2). Kombucha tea is contraindicated for pregnant and lactating women, and may be unsafe for people who are immune compromised.
Given the interest in the effect of the microbiome on health, and the effect of fermented foods (yogurt, miso, tempeh, kimchi, etc.) on the microbiome, more human studies involving kombucha tea are anticipated. Watch for an upcoming PEN® Practice Question on kombucha tea.
- Jayabalan R, Malbaša RV, Lončar ES, Vitas JS, Sathishkumar MA. Review on kombucha tea – microbiology, composition, fermentation, beneficial effects, toxicity, and tea fungus. Comprehensive Reviews in Food Science and Food Safety. 2014 July;13(4). Available from: http://onlinelibrary.wiley.com/doi/10.1111/1541-4337.12073/full
- Therapeutic Research Faculty. Natural
Medicines Comprehensive Database. [cited 2016 Nov 11]. Available
Revised November 17, 2016
Supplements Associated with Liver Injury
With the increased use of herbal and dietary supplements worldwide, there has also been an increase in reports of liver injury attributable to their use (1). “Herbal and dietary supplement-related liver injury now accounts for 20% of cases of hepatotoxicity in the US” with rates of hepatotoxicity from herbal and dietary supplements in Europe ranging between 13-16% of cases and Asian countries reporting even higher rates. Anabolic steroids, green tea extract and supplements with multiple ingredients are the products most commonly linked to the hepatotoxicity in the US. See: Liver Injury from Herbal and Dietary Supplements.
Dietitians may also find this open access article on the hepatotoxicity of dietary supplements to be of interest. A literature search was performed in PubMed to identify English and Spanish case reports, case series and clinical reviews published from 1984 to 2015 that described reports of liver injury associated with dietary supplement and/or herbal product use (2). Products examined included: anabolic steroids, green tea extract, linoleic acid, usnic acid, 1,3-Dimethylamylamine, vitamin A, Garcinia cambogia and ma huang as well as multi-ingredient products Herbalife™ products, Hydroxycut™, LipoKinetix™, UCP-1 and OxyELITE™. They found that the prevalence of herbal and dietary supplement-induced liver injury is increasing worldwide.
Hepatotoxicity can result in anything from mildly uncomfortable symptoms, such as nausea and vomiting to, in extreme circumstances, complete liver failure. Dietary supplements are not benign substances and their safe use requires awareness of potential side-effects.
This information reminds dietitians to be sure to delve into their clients' use of supplements, paying specific attention to the type of product used and whether people are taking the recommended amounts or using them in ways that put them at risk for adverse events. Staying abreast of the literature on efficacy of dietary supplements as well as their safety is critical. A good place to start is the PEN® System. There are more than 190 practice questions and 35 background documents identified in the search for dietary supplements.
- Navarro V, Khan I, Björnsson E, Seeff LB, Serrano J, Hoofnagle JH. Liver injury from herbal and dietary supplements. Hepatology. 2016 Sep 27 [Epub ahead of print]. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/27677775
- García-Cortés M, Mercedes Robles-Díaz M, Aida Ortega-Alonso A, Medina-Caliz I, Andrade RJ. Hepatotoxicity by dietary supplements: a tabular listing and clinical characteristics. Int J Mol Sci. 2016;17(4):537. Abstract available from: https://www.ncbi.nlm.nih.gov/pubmed/27070596
Article Analysis: Calcium and Heart Health
Tax and Sugar-sweetened Beverages
The World Health Organization (WHO) recommends taxing sugar-sweetened beverages (SSB), such as pop/soft drinks/soda, fruit drinks, sport drinks, energy and vitamin water drinks, and sweetened iced tea and lemonade, to lower consumption and to reduce the risk of obesity, type 2 diabetes and tooth decay worldwide. In February 2016 Dietitians of Canada also recommended taxation on SSB
. Listen to a recent eight-minute Viewpoint Podcast
interview with Kate Comeau from Dietitians of Canada. Within the WHO report
, it states, "The evidence for meaningful health effects is strongest for taxes on SSB, with suggestions that SSB prices would need to be raised by 20%, or more. Such taxes lead to more than proportional reductions in SSB consumption and net reductions in caloric intake, and thus contribute to improving nutrition and reducing overweight, obesity and NCDs. Similarly strong evidence shows that subsidies for fresh fruits and vegetables, that reduce prices by 10-30%, are effective in increasing fruit and vegetable consumption". WHO further suggests that funds raised go toward fruit and vegetable subsidizes. See Additional Content: What interventions can help reduce consumption of energy from SSB in children?
Cardiovascular Guideline Releases