A recent Australian study looked at whether consuming excessive amounts of sugar can affect the intake of micronutrients.
The consumption of too much sugar can lead to serious health problems including obesity, dental problems, and chronic diseases, such as diabetes. In light of these problems, health authorities around the world have developed guidelines advising how much free sugars we should be consuming. However, as these guidelines were developed with specific health goals in mind, the advice is often inconsistent.
The World Health Organization (WHO) recommends that our free-sugar intake should contribute up to 10% of our daily total energy intake to help prevent dental disease. Their definition of free sugars included all added sugars and natural sugars found in honey, syrup, and fruit juices. In contrast, the Institute of Medicine recommends a much higher limit of 25%, which accounts for micronutrient dilution. This occurs when consumption of negative nutrients, or free sugars, causes a decrease in the intake of micronutrients, which include essential vitamins and minerals.
How Much Sugar is Too Much?
A cross-sectional study recently published in the American Journal of Clinical Nutrition aimed to establish accurate thresholds for free-sugar consumption to better understand the association between free-sugar and micronutrient intake. The investigators obtained dietary intake data from the 2011-2012 Australian Health Survey. During this survey, 6,150 Australian adults completed two 24-hour recall questionnaires in which they listed all foods they had consumed in the 24 hours prior to the interview.
The interviewers assessed the micronutrient and free-sugar content of each food and drink product. They used this information to classify the participants into one of six categories representing the percentage of free-sugar they consumed as a percentage of total energy intake. The effects of free-sugar intake on micronutrient intake and on the intake of core (the five healthy food groups) and discretionary food groups were analyzed. The researchers also took age, sex, socioeconomic status, diet and smoking status, country of birth, and geographical living area into consideration.
Approximately half of the participants (47%) consumed more free sugars than recommended by the WHO. These individuals were more likely to be young men from a lower socioeconomic background. They were also more likely to live in major cities and to have been born in English-speaking countries. As one would expect, the participants with a higher free-sugar intake consumed less of all core food groups excluding dairy but consumed more discretionary foods.
Micronutrient Intake Decreases with High or Very Low Sugar Intakes
Significant reductions in the intake of most micronutrients, except sodium, were not observed until the free-sugar intake was over 25% of the daily total energy intake. Only 1.3% of participants fell into this category, which corresponded to the upper limit set by the Institute of Medicine. Along with the health issues posed by consuming excessive amount of sugar, there is a risk that individuals in this category are not receiving their recommended daily dose of various micronutrients. The peak intake for most micronutrients occurred when the percentage of free-sugar intake was between 5-15% of the daily total energy intake. Interestingly, once the free-sugar intake fell below 5% of the daily total energy intake, the intake of some micronutrients – including calcium, folate, and riboflavin – also fell below the recommended daily doses. The investigators emphasized that this was likely due to inadequate total energy intake.
Although this study did not look at whether the participants were taking micronutrient supplements and the questionnaire results were subject to possible bias, the results highlight the importance of striking the correct balance between free-sugar and micronutrient intake. Where a high free-sugar intake (over 25% of the daily total energy intake) diluted most micronutrients, a very low free-sugar intake (less than 5% of the daily total energy intake) also resulted in suboptimal micronutrient intake. The authors suggest that strategies for reducing free-sugar intake should promote healthy food choices rather than concentrating on staying within the recommended limits.
Written by Natasha Tetlow, PhD
Reference: Mok A, Ahmad R, Rangan A, Louie JCY. Intake of free sugars and micronutrient dilution in Australian adults. Am J Clin Nutr. 2018;107:94-104.