Nutrition Myth Buster

Background
Nutrition Myth Buster
Abstract

Debunk the common nutrition myths and reveal the truths with WNSC HK!

17 min read

Are these MYTHS or FACTS?
Click on the statement to reveal the answers!
 

General Nutrition

Pediatric Nutrition

Maternal Nutrition

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General Nutrition
 

“When consuming eggs, I should go for only the whites and avoid the yolk because of its high cholesterol content." 

MYTH!

Despite the relatively high cholesterol content in egg yolks, up to this date there has been insufficient evidence to suggest a quantitative limit of cholesterol intake1 nor to associate egg consumption with risks of cardiovascular diseases2. The egg yolk contains abundant amounts of vitamins A, D, E, K, B1, B2, B5, B6, B9, B123 and is a major source of choline which helps modulate gene expression, cell membrane signaling and also early brain development4. Based on a survey done by the Centre of Health Protection in April 2007, 84.2% of male and 93.2% of female in Hong Kong consumed an average of less than one egg per day5. The Hong Kong Department of Health recommends adults to have 5-8 taels (兩) of meat each day, with one tael as equivalent to meat in the size of a table tennis ball or a whole egg (including egg yolk)6.

Learn more with WNSC HK:
WNSC Hong Kong Food Group Exchange Tips Card (Meat)

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“When a food product is ‘organic certified’, it guarantees that 100% of the ingredients originates from organic sources and are completely free of synthetic fertilizers, pesticides, or genetical modifications.”

MYTH!

According to the Codex Alimentarius, “Organic” is a labelling term which indicates products that have been produced in accordance with organic standards and certified by a duly constituted certification body or authority7. While organic agriculture actively minimizes the use of external inputs and avoids the use of synthetic fertilizers and pesticides, it cannot be guaranteed that organic products are completely free of residues due to general environmental pollution7.

The requirements of organic food production and labelling varies among different certification bodies. The European Union (EU) requires that all processed food products labelled “organic” must have at least 95% by weight of its ingredients from organic agricultural origin8. While there is a lack of specific regulations governing the production, certification and labelling of organic foods in Hong Kong9, the Hong Kong Organic Resource Centre (HKORC) has been providing voluntary certification service to local farmers since December 2002 with funding from the Agricultural Development Fund under the Vegetable Marketing Organization10.  In order to make informed choices on purchasing, consumers are encouraged to carefully read organic labels before making their decisions11.

Learn more with WNSC HK:
WNSC Hong Kong Bulletin 2017 Issue 2 – Organic food
Center for Food Safety – Organic certification and labelling

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“Cow’s milk is the most commonly consumed dairy product in the world.”

MYTH!

Although cow’s milk has remained its dominance in the global dairy industry, there is in fact 65-72% of the world’s population12 who consume dairy products from goats, more than that of any other single species13. Due to the insufficient supply of cow’s milk, goat’s milk and its products serve as important daily source of protein, phosphate and calcium for populations in developing countries13. When compared to cow’s milk, the milk of goat is slightly lower in lactose and protein; similar in calcium, iron, vitamin D and vitamin C; and significantly higher in phosphorus, vitamin A, vitamin B1 and vitamin B214. In view of the increasing demand of this alternative dairy source, goat milk research has rapidly advanced throughout the past century from the fundamental understanding of its composition to its introduction as an ingredient in food products such as milk formulas15.

Learn more with WNSC HK:
WSNC Hong Kong Bulletin 2019 Issue 4 – 10 quick facts about goat milk 

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“Cold-pressing extracts juice from fruits and vegetables without destroying or losing any of the nutrients, hence, is a healthier option as compared to conventional juice." 

MYTH!

Regular juices are normally extracted in juicers utilising a fast-spinning metal blade juxtaposed against a mesh filter, where the juice extract will be separated from the fruit flesh by centrifugal force16. There are claims that this spinning process at a very high speed generates heat, thereby damaging and reducing the bioactive compound content in juices. On the other hand, cold-pressed extractors crush and press the fruit at a very low speed, which generates minimal heat and helps to maintain the nutritional quality of the juice according to some manufacturers. However, there is generally a lack of evidence for these claims and a recent study also raised some questions in this respect1. Khaksar et al (2019) found no significant differences in the antioxidant capacity and bioactive compound contents (ascorbic acid, total phenolic, and total carotenoid contents) between cold-pressed and regular centrifugal juice16. To note, nutritional quality of juices can be highly variable based on juicing conditions such as the time and speed, while considerations should also be given to storage temperature and time-period that contribute to the degradation of some bioactive components16. Regardless of the preparation method, pure fruit juices often have lower nutritional value than whole fruits with their higher energy and sugar content levels, and therefore consumption of whole fruit is encouraged instead as part of healthy eating17.

Learn more with WNSC HK:
AAP recommendations on fruit juice consumption in infants and children

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Pediatric Nutrition

“Exclusively breastfed infants are at no risk of nutrient deficiencies.”

MYTH!

Babies may be at risk of vitamin D deficiency, if, with no sunlight exposure or were born to mothers with vitamin D deficiency, especially if they are breastfed exclusively18. The American Academy of Pediatrics (APP) recommends all infants and children to have a minimum intake of 400 IU of vitamin D per day starting soon after birth19. Meanwhile, the Chinese Dietary Reference Intake 2013 recommends a daily intake of 10 mcg/day vitamin D for pregnant and lactating women, as well as women of child-bearing age (18-50 years)20.  

Learn more with WNSC HK:
WNSC Hong Kong Info Card – Vitamin D fact sheet

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“Prebiotics such as galacto-oligosaccharides (GOS), fructo-oligosaccharides (FOS) and inulin are all oligosaccharides naturally found in human milk.”

MYTH!

While being commonly used as ingredients for food products such as milk formula for their prebiotic properties, these non-digestible carbohydrates are structurally very different from oligosaccharides naturally found in human milk (i.e. human milk oligosaccharides, HMOs)21. For example, galacto-oligosaccharides (GOS) are synthetic mixtures of oligosaccharides derived from the enzymatic glycosylation of lactose which typically consist of two to ten molecules of galactose and 1 molecule of glucose21; whereas HMOs are characterized by having a lactose backbone bounded to various types of residues such as a fucose molecule at the galactose terminal end (to form 2’-fucosyllactose, 2’-FL). Since most of the functional properties of HMOs are thought to be structure-specific, it is unlikely that the above prebiotic ingredients can provide similar health benefits as described for HMOs21.

Learn more with WNSC HK:
WNSC Hong Kong Info Card – A practical guide to understanding prebiotics

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“The immune system begins to development at the moment a baby is born.”

MYTH!

As early as the fourth week into pregnancy, hematopoietic progenitor cells (immune cell precursors) are already undergoing rapid cell division and traveling through the blood into organs associated with the immune system, such as the liver and spleen23. These cells then mature into T cells which are organized into Peyer’s Patches, the specialized lymph nodes in the fetal intestine, by about 19 weeks of gestation. Starting from the moment of birth, these T cells play a major role in the governance of B cells adaptive immune response by generating antibodies as well as low levels of cytokines. As the best form of nutrition for babies, human milk provides an extensive range of bioactive components which altogether supports the normal growth and development of the neonate24. Alongside key nutrients for immune development (such as vitamins A, C, D, E, iron, zinc and selenium), specific types of human milk oligosaccharides (HMOs) including 2’-fucosyllactose (2’-FL) and Lacto-N-neotetraose (LNnT) have been clinically shown to modulate the young gut microbiome to one associated with less antibiotic use during the first 12 months of life25.

Learn more with WNSC HK:
WNSC Hong Kong – Human milk oligosaccharides (HMOs): magic bullets for optimal immune health 

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“Avoiding or delaying the introduction of foods such as eggs, peanuts and fish would prevent a child from developing food allergies."

MYTH!

The current consensus and recommendations by experts do not support the need to delay allergenic food introduction to prevent allergy. According to the latest 2019 American Academy of Pediatrics (AAP) clinical report on the effects of early nutritional interventions on the development of atopic disease in infants and children, there is no evidence that delaying the introduction of allergenic foods such as eggs, peanuts and fish beyond 4 to 6 months can help to prevent atopic disease26. On the contrary, based on the Learning Early About Peanut Allergy (LEAP) trial, AAP concluded there is now evidence that the introduction of infant-safe forms of peanuts as early as 4 to 6 months of age in infants at high risk of peanut allergy (those with severe eczema and/or egg allergy) may help to reduce the development of peanut allergies27. Locally, the Hong Kong Institute of Allergy (HKIA) recommended introduction of complementary food from 4 to 6 months of age when developmentally ready as one of the allergy prevention measures28. The HKIA position paper also pointed out there was emerging evidence that the risk of food allergy or eczema may actually increase when solid food with potent food allergens are introduced after 6 months28.

Learn more with WNSC HK:

Expert interview with Dr. Marco Ho – The forefront of allergy prevention in the Hong Kong paediatric population

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“Artificial sweeteners have adverse effects on children's health and should not be consumed as part of their diet."

MYTH!

While there have been different voices on the usage of artificial sweeteners and some questions still remain on long-term safety, usage in children have been associated with less dental caries and weight stabilization or weight loss in the short-term according to a review by AAP in 201929. Contrary to popular opinion, there was no association found between artificial sweetener consumption and hyperactivity. While no advice could be provided for children younger than 2 years old due to absence of scientific data, AAP concluded there are no absolute contraindication in the usage of artificial sweeteners in older children, except for the case of aspartame and neotame in those with phenylketonuria.

Learn more with WNSC HK:
WNSC HK Food Group Exchange Tips Card (Sugars)

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Maternal Nutrition

“A mother should stop breastfeeding if she has mastitis.”

MYTH!

Breastfeeding during mastitis generally does not pose a risk to infants and should be continued to help maintain milk supply30. Milk stasis is a common initiating factor in mastitis and therefore effective milk removal is critical. Mothers with mastitis are encouraged to breastfeed more frequently, starting on the affect breast31. Proper positioning of infants, messaging the breast and other measures like adequate fluids and nutrition can also help31. If symptoms do not improve within 12-24 hours or the mothers are acutely ill, antibiotic treatment should be started31.

Learn more with WNSC HK:
WNSC Hong Kong Info Card 2018 Issue 1 Mastitis Fact Sheet

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“Supplementation of alpha-linolenic acid (ALA) (i.e. flaxseed oil) during pregnancy can provide sufficient DHA to support fetal growth.”

MYTH!

ALA is a precursor for synthesizing longer chain omega-3 fatty acids, but human body conversion of ALA to DHA is < 5% in general and is very dependent on the levels of omega-6 fatty acids and long chain polyunsaturated fatty in diet32,33During pregnancy and lactation where demand for DHA increases significantly, conversion of ALA to DHA may be insufficient to meet the body need32. Following expert recommendations would better support the nutritional need during pregnancy and lactation:

  • Chinese Dietary Reference Intakes (DRIs): 200 mg of DHA daily34
  • FAO/WHO: 200 mg of DHA daily35

Learn more with WNSC HK:
WNSC Hong Kong Info Card 2017 Issue 1 – DHA Fact Sheet

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“According to expert recommendations, a healthy diet rich in folate alone during preconception and early pregnancy to support healthy pregnancy outcome.”

MYTH!

For couples with no personal or family risk of neural tube defect or folic acid-sensitive birth defect, the Society of Obstetricians and Gynaecologists of Canada (SOGC) advices women to take multivitamin with 0.4 to 1.0 mg of folic acid together with a healthy folate-rich diet for 2-3 months before conception and throughout pregnancy. This should be continued for 6 weeks postpartum or until completion of breastfeeding36.

Learn more with WNSC HK:
[Literature Library] Recommendation statement on folic acid supplementation

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“Taking a multivitamin/multimineral supplement during pregnancy causes constipation."

MYTH!

Although it is perceived that iron and/or calcium content in supplement leads to constipation during pregnancy, no evidence showing a concrete relationship between multivitamin/multimineral supplementation and constipation during pregnancy has been noted as per literature search.

Indeed, a randomized and double-blinded study has demonstrated no significant differences of gastrointestinal symptoms like constipation among healthy pregnant women taking 20, 40, 60 and 80 mg of iron supplement37. Nguyen P et al (2008) showed no significance in rates of reported adverse events like constipation in pregnant women consuming multiple vitamins and minerals formulated into 2 tablets (iron and calcium separated into morning and evening tablet) and one tablet containing both iron and calcium together with other nutrients38.

Approximately 40% of pregnant women experiences constipation39. In Hong Kong, an overall prevalence of constipation was 14.3% with a female to male ratio of 1.3:1.0 in a population-based survey (n = >3,000 adults)40. It is very important for Hong Kong women, pregnant women in particular, to follow advices on supporting gastrointestinal health41:

  • Drink plenty of fluid like plain water, 6 – 8 cups daily
  • Increase intake of foods high in dietary fiber, i.e. brown rice, whole grain cereals, vegetables and fruits especially prunes and figs

Learn more with WNSC HK:
Summary of the German National Consensus Recommendations on Nutrition and Lifestyle in Pregnancy

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“Women do not need extra vitamin D during pregnancy."

FACT!

For a healthy female aged 18 to <65 years, the recommended nutrient intake (RNI) of vitamin D set by Chinese Nutrition Society is 10 mcg per day and no additional requirement is needed during pregnancy and lactation42.

Nevertheless, vitamin D insufficiency has been reported in Hong Kong population since 2008 with >90% of women of child-bearing age having insufficient vitamin D level in their body (≤ 50 nmol/L)43. Over 70% (141 out of 196 subjects) of Hong Kong young adults showed vitamin D deficiency (< 50 nmol/L) in a 2018 report44.

A few foods contain vitamin D naturally and examples include fatty fish (e.g. salmon, sardines, tuna), egg yolk and liver45. Getting exposure to sunlight may also help since 5 to 15 minutes of sun exposure of hands, face and arms 2 to 3 times weekly during summer is enough to maintain adequate vitamin D level for most people45.

Learn more with WNSC HK:
WNSC Hong Kong Info Card 2017 Issue 4 – Vitamin D Fact Sheet

WYE-EM-118-MAY-20
WYE-EM-148-JUN-20

Reference
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  6. Hong Kong Department of Health. No more limits on amount of cholesterol intake? Available at https://www.chp.gov.hk/en/static/90041.html. Accessed on 22Apr2020.
  7. Codex Alimentarius. GL 32-1999 Guidelines for the production, processing, labelling and marketing of organically produced foods. 2013.
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