PEN eNews 11(1) January 2021

Raw Food Diets - What is the Latest?

The Question

Are there any positive or negative health outcomes associated with following a raw food diet compared to following vegetarian, vegan or non-vegetarian diets?

The Recommendation

For those committed to following a raw food diet, the following are areas that may benefit from attention:

ensuring that energy and nutrients needs are being met to support body functioning, bone health and general health
designing the diet to support the bioavailability of the nutrients ingested (such as adequate fat to absorb the fat-soluble nutrients and phytochemicals such as lycopene and carotenoids)
ensuring products chosen for consumption are food safe.

Evidence Summary

Cross-sectional research studies on individuals who have followed a raw food diet for a number of years found low BMIs and high rates of underweight amenorrhea. There was also some evidence of lower bone mineral content and bone mineral density among raw foodists versus controls. Energy intakes tend to be low and fruit and vegetable intakes are very high (few kg per day) and fibre intakes are generally high at a mean of 60 g/day. While the diet is very high in carotenoids and rich in lycopene, this intake has not always translated into higher levels in the plasma, potentially due to the lower fat intakes and higher fibre intakes that could impact bioavailability. Folate and vitamin B6 intakes are generally good though vitamin B12 intakes and status can be low depending on the diet. It should be noted that the raw food diet is not necessarily vegetarian or vegan and in fact anywhere from approximately 25-57% of those following the raw food diet ate animal products (smoked, raw or semi-cooked). Serum lipid profiles tended to be in the desirable ranges. Microbiological analysis of buckwheat cookies made for the raw food diet (prepared with soaking and then drying between 40 and 60°C) indicated microbial risks with the end product.

To see the full practice question, including the Evidence Statements and References, click here.

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Surprising Findings: GRADE meets the Nutrition Media

A colleague recently alerted me to an article, Nutrimedia: a novel web-based resource for the general public that evaluates the veracity of nutrition claims using the GRADE approach (1). Very intriguing!

GRADE Refresher

Many of us have heard of GRADE (Grading of Recommendations, Assessment, Development and Evaluation), a transparent approach for evaluating the certainty of evidence for each outcome of an intervention (i.e. high, moderate, low or very low). Clinical practice guidelines can use this graded evidence to report the strength of recommendations (i.e. strong or conditional). Not all systematic reviews and guidelines use this approach, so PEN^® evidence reports if GRADE evaluation has been done and uses the PEN GRADE Process to develop the evidence and recommendations for some PEN questions (e.g. cardiovascular disease, ketogenic diet and diabetes, malnutrition, oral health, osteoarthritis).

What is unique about Nutrimedia?

Nutrimedia is a Spanish-based initiative designed to evaluate the accuracy of various nutrition claims for the public. (It is a Spanish website so has limited capacity for English translation). It is a joint project between Iberoamerican Cochrane Centre and Pompeu Fabra University. To develop Nutrimedia, the Spanish researchers examined some nutrition claims (e.g. common beliefs reported in the media or in advertising and those collected from the public from an online survey). After assessing the certainty of the body of evidence using the GRADE approach, they classified the veracity of these claims into seven categories: true, probably true, possibly true, false, probably false, possibly false and uncertain. Claims supported by high certainty evidence were described as true or false. Lower certainty evidence was communicated using language modifiers: probably true/false for moderate certainty evidence, possibly true/false for low certainty evidence, uncertain for very low certainty evidence. They also developed plain language summaries of the evidence and engaging online tools to explain the evidence for the end user.

How does Nutrimedia stack up against PEN Recommendations?

In the published article, the authors summarize 30 nutrition claims (up to May 2019), almost half of which were classified as uncertain (1). Most evaluations (70%) were about specific food products.

Table 1. Comparison of Nutrimedia and PEN recommendations on selected topics

Topic	Nutrimedia - Veracity of Claim	PEN Recommendation
Soy products effect on menopausal symptoms	Uncertain if soy products are effective in treating menopause symptoms (vasomotor, vaginal, cognition)	“..soy foods and phytoestrogen supplements are unlikely to improve quality of life or overall menopause symptom scores…Adverse events of supplementation are negligible”. Grade C (limited evidence)
Meat and carcinogenicity	Possibly true that red meat/processed meat increases the risk of colorectal cancer	“Limiting the consumption of processed meat (little to none) may reduce the risk of colorectal cancer. Limiting the consumption of red meat (<350-500 g/week cooked) or foods containing heme iron (including red and processed meat, fish and poultry) has smaller and uncertain benefits on reducing the risk of colorectal cancer.” Grade B (fair evidence)
Eggs and cardiovascular disease	Uncertain whether habitual egg consumption increases the risk of cardiovascular disease	“For primary CVD prevention, we suggest not restricting dietary cholesterol intake or egg consumption.” Conditional recommendation, very low quality evidence

Table 1 shows that the assessment of the quality of evidence for the selected topics was similar between the two tools. Nutrimedia evaluates the veracity of the nutrition claim. The PEN System provides an overall recommendation for practitioners that considers benefits and risks based on important outcomes of a nutrition intervention.

Where do we go from here?

Nutrimedia is a Spanish website that uses the GRADE approach to evaluate nutrition media claims for the public using an easily understood classification system (e.g. true, false). It also provides online plain language summaries and web-based tools to support the message. The authors report good traffic to their website; however, they have not tested how well the seven-point scale communicates uncertainty to the public. Limitations include the challenges in translation, that few nutrition claims have been evaluated, and that there is no system in place to monitor and update the evaluations.

Like Nutrimedia, the PEN System also dispels nutrition myths through practice-based nutrition questions using a rigorous evidence grading system including GRADE, but the PEN System is a robust database that examines evidence for thousands of nutrition questions relevant to dietetic practice. The PEN System translates evidence into recommendations for nutrition professionals considering important outcomes of interventions; in turn these recommendations are translated into evidence-based advice in PEN handouts. The PEN database is dynamic and strives to maintain currency and incorporate high quality evidence that impacts practice recommendations in a timely manner.

It is great that researchers are investigating ways of communicating GRADE results directly to the general public and I look forward to expansion of this work.

Written by:

Dawna Royall MSc, RD, FDC
PEN^® Senior Evidence Analyst

References

Rabassa M, Alonso-Coello P, Casino G. Nutrimedia: a novel web-based resource for the general public that evaluates the veracity of nutrition claims using the GRADE approach. PLoS One. 2020 Apr 30;15(4):e0232393. doi: 10.1371/journal.pone.0232393. PMID: 32353048; PMCID: PMC7192410. Abstract available from: https://pubmed.ncbi.nlm.nih.gov/32353048/

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PEN eNews 11(1) January 2021

Raw Food Diets - What is the Latest?

The Question

The Recommendation

Evidence Summary

The Infant Colic Knowledge Pathway is Updated!

Open Access to COVID-19 Content Continues

Surprising Findings: GRADE meets the Nutrition Media

GRADE Refresher

What is unique about Nutrimedia?

How does Nutrimedia stack up against PEN Recommendations?

Where do we go from here?

References

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