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Does eating sugar compromise nutrient intake?

Hand picking up pink iced doughnut.jpgAre diets higher in sugar less nutritious? Is there a ‘micronutrient dilution’ effect?  The evidence suggests that - like many other complex nutrition issues - it depends.

How high is too high?

When it comes to added sugars, having too much may come at a nutritional cost. A systematic review on sugar intake and micronutrient adequacy found there is a marginal nutrient dilution affect when the proportion of added sugars reaches 20% of energy[i]. Interestingly, diets with moderate amounts of added sugars were actually more likely to contain optimal micronutrient intakes; the relationship is an n-shaped curve with lower micronutrient intakes at both low and high intakes of added sugars and a ‘sweet spot’ within moderate intakes. The same association was found in another review by Ruxton and colleagues who found nutrient adequacy was achieved across intakes of 6-20% energy [ii]

Considering added sugars intake of Australians is moderate (10.9 % energy from free sugars [iii]), it is likely to be supporting optimal nutrient intake rather than diluting it.

Another systematic review by Rennie and colleagues found no clear evidence of micronutrient dilution or a threshold for added sugar intake for any of the micronutrients investigated but said insufficient data, inconsistency between studies and methodological issues hampered their review [iv]. No clear micronutrient dilution effect was also found by Gibson and colleagues in their systematic review – any inverse associations for sugars and micronutrient intake were weak, with sugars explaining less than 5% of the variance. Gibson stated the available evidence didn’t allow for firm conclusions on an optimal level of added sugars intake for micronutrient adequacy, and the trends that exist may have little biological significance.

 A very recent study published this year from the Netherlands found adherence to the WHO 10% free sugar guideline was not strongly associated with higher diet quality in adults although adherent adults did consume more dietary fibre and vegetables. Interestingly, adherence to the WHO sugar guideline was low - especially in children - with only 5% children consuming less than 10% energy as free sugars; and only 30% of adults [v].

What about children?

Children tend to be higher consumers of added sugars than adults, and their nutrient needs are higher to support growth and development. Could they be at greater risk of micronutrient dilution? A study examining the 2007 Australian National Children’s National Nutrition and Physical Activity Survey (ANCNPAS) data found a nutrient dilution effect at the highest quintile of added sugars intake (mean 17.2% energy) but the associations were small: a change of 1% or less in nutrient intake per unit increase in percent energy from added sugars [vi]. These results are similar to studies conducted in Ireland [vii] and Great Britain [viii]. A recently published British study [ix] of free sugars intake and nutrient intakes in children and adolescents from their most recent National diet and nutrition survey found associations with micronutrients were mostly non-significant, but there were significant negative associations for 11-18 year olds with zinc, selenium, Iron, copper and vitamins A and D. Children who consumed average amounts of free sugars or above (>13% energy) had lower dietary quality than those with

What about the elderly

The elderly are another nutritionally vulnerable group. An Australian cross sectional study of older people [x] found energy intake from added sugar greater than 10% of energy was associated with lower micronutrient intakes, indicating a micronutrient dilution effect. Moreover, those consuming less than 5% of energy as added sugar had higher micronutrient intakes except for calcium, folate and vitamin D.  Unfortunately, the authors were unable to compare nutrient intakes with estimated requirements to assess adequacy.  Higher consumers had higher intakes of energy-dense, nutrient-poor foods, while lower sugar consumers drank more alcohol suggesting a switch from sweetened to alcoholic drinks. This result contrasts with others who have found moderate intakes of 8-15% energy from added sugars does not compromise nutrient intake in older adults [xi].

The source of sugar matters

When it comes to added sugars and nutrient intake the source of added sugars is significant. The European Food Safety Authority (EFSA) concluded the observed negative associations between added sugars intake and micronutrient density are related to patterns of intake of high-sugar foods themselves rather than added sugars per se [xii]. Nutritionally adequate diets with higher levels of added sugars may reflect sugar consumed in nutrient dense foods such as fortified breakfast cereals and dairy products, or in the case of free sugars, fruit juices.

The Study of Australian children and adolescents mentioned above found an increased risk for not meeting the Nutrient Reference Values (NRV) with increased energy from added sugars (%EAS). For each unit increase in percent energy from added sugars (%EAS), the increase in risk for not meeting the NRV for Australia and New Zealand ranged from 5% for iodine to 37% for riboflavin. However, stratifying the source of added sugars revealed that this negative relationship only existed for added sugars from ‘extra’ (discretionary) foods in most cases. Sub group analysis showed the %EAS was strongly positively associated with intake of sugar-sweetened beverages.

Consuming fewer discretionary foods and drinks-especially sugar sweetened beverages- has the potential to reduce added sugars and improve nutrient intake.

Gibson et al in their analysis of children’s free sugar intake concluded, “Ultimately, nutrient intakes depend on the total dietary pattern; however, reducing overconsumption of sugary foods and drinks with low nutrient density may help improve dietary quality.”

Conclusions

  • There is some evidence for a micronutrient dilution effect at high levels of added sugars consumption (>20% energy), however this is higher than usual intakes.
  • The elderly may be at greater nutritional risk at above recommended added sugar intakes
  • Optimal levels of micronutrient intakes tend to be within diets that contain moderate levels of added sugars
  • The highest nutritional risk comes from diets with too many nutrient-poor discretionary foods
 

NEXT: The big issue: discretionary foods 

REFERENCES

[i] Gibson, S. A. (2007). Dietary sugars intake and micronutrient adequacy: a systematic review of the evidence. Nutr Res Rev, 20, 121-31.

[ii] Ruxton CH, Gardner EJ, McNulty HM. Is sugar consumption detrimental to health? A review of the evidence 1995-2006. Crit Rev Food Sci Nutr 2010;50(1):1-19. doi: 10.1080/10408390802248569. Available at URL https://www.ncbi.nlm.nih.gov/pubmed/20047137

[iii] Australian Bureau of Statistics. 4364.0.55.011 -Australian Health Survey: consumption of added sugars 2011-12. Available at URL http://www.abs.gov.au/ausstats/abs@.nsf/mf/4364.0.55.011

[iv] Rennie KL, Livingstone MB. Associations between dietary added sugar intake and micronutrient intake: a systematic review. Br J Nutr 2007;97(5):832-41 Available at URL https://www.ncbi.nlm.nih.gov/pubmed/17408523?dopt=Abstract

[v] Sluik D, van Lee L, Engelen AI, Feskens EJ. Total, free, and added sugar consumption and adherence to guidelines: the Dutch National Food Consumption Survey 2007-2010. Nutrients 2016;8(2):70. doi: 10.3390/nu8020070. Available at URL https://www.ncbi.nlm.nih.gov/pubmed/26828518

[vi] Louie, J.C.Y. & Tapsell, L.C. (2015). Intake of total and added sugars and nutrient dilution in Australian children and adolescents. Br J Nutr doi:10.1017/S0007114515003542. Available at URL https://www.cambridge.org/core/journals/british-journal-of-nutrition/article/intake-of-total-and-added-sugars-and-nutrient-dilution-in-australian-children-and-adolescents/8D72197DC0709CEF27C90995029A2EB2/core-reader

[vii] Joyce T & Gibney MJ. The impact of added sugar consumption on overall dietary quality in Irish children and teenagers. J Hum Nutr Diet 2008; 21: 438–450

[viii] Gibson S & Boyd A. Associations between added sugars and micronutrient intakes and status: further analysis of data from the National Diet and Nutrition Survey of Young People aged 4 to 18 years. Br J Nutr 2009;101: 100–107.

[ix] Gibson S, Francis L, Newens K, Livingstone B. Associations between free sugars and nutrient intakes among children and adolescents in the UK. Br J Nutr 2016;116(7):1265-1274 Available at URL https://www.ncbi.nlm.nih.gov/pubmed/27641637

[x] Moshtaghian H, Louie JC, Charlton KE et al. Added sugar intake that exceeds current recommendations is associated with nutrient dilution in older Australians. Nutrition 2016;32(9):937-42 Available at URL https://www.ncbi.nlm.nih.gov/pubmed/27155956

[xi] Gibson S. Dietary sugars and micronutrient dilution in normal adults aged 65 years and over. Public Health Nutr 2001;4:1235-44. Available at URL https://www.ncbi.nlm.nih.gov/pubmed/?term=Dietary+sugars+and+micronutrient+dilution+in+normal+adults+aged+65+years+and+over

[xii] EFSA (2010) Scientific Opinion on Dietary Reference Values for carbohydrates and dietary fibre. EFSA Journal, 8, 1462.

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