20120727 - Health claims and the BNI of yogurts - 2011

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[<Normal page] [PEREZGONZALEZ Jose D (2011). Health claims and the BNI of yogurts. Journal of Knowledge Advancement & Integration (ISSN 1177-4576), 2012, pages 231-233.]

Table of Contents

Health claims and the BNI of yogurts

Generalization potential

Health claims and the BNI of yogurts

Health-related claims are commonly used when marketing yogurts. As many of these claims cannot be legally made unless products meet such claims, it is of little interest to test the truth of individual claims. However, it is of interest to test whether such claims inform about overall nutritional balance (BNI). This way, a consumer may rely on any significant claim for choosing more balanced products. This article summarizes research done in this regards (for an in-depth description see Perezgonzalez, 2011c³).

Illustration 1 collates relevant statistical information about a claim commonly appearing on yogurts: heart health⁴. The results seem to support several inferences. Firstly, that yogurts with 'heart health' claims have an average BNI lower (median = 89.62) than other yogurts (median = 93.59). Secondly, that such difference is also found between groups (U = 9374, p < 0.01). And thirdly, that there is a correlation supporting a trend between sporting a heart health claim and the yogurt having lower nutritional unbalance (rho = -0.211, p < 0.01). In any case, even when statistically significant, both the difference in medians and the correlation are rather small, and they may not be that important in practical terms.

Illustration 1: Health claims on yogurts
Claim »	Heart health
BNI	No	Yes
0	0	0
<10	0	0
<20	0	0
<30	0	0
<40	2	0
<50	0	0
<60	4	2
<70	21	13
<80	10	13
<90	46	39
<100	68	33
<110	48	8
<120	24	0
<130	8	1
<140	2	0

Median	93.59	89.62
U (p)	9374.0	( .000 )
rho (p)	-.211	( .000 )
(Sig ≤ 0.05, 2-tailed; source: Perezgonzalez, 2011b²)

Methods

Research approach

Exploratory study.

Sample

A stratified sample of 342 yogurts (ie, soy and cow's milk yogurts, natural and flavored yogurts, and fat-free, low-fat, standard and creamy yogurts), collected in a convenient manner (see Perezgonzalez, 2011b²).

Materials

The main (or dependent) variable was the balanced nutrition classification as assessed using the Balanced Nutrition Index™ (BNI™) technology (see Perezgonzalez, 2011a¹).

The grouping (or independent) variables were whether products sported health-related claims such as heart-health (eg, the Heart Foundation's "Tick" logo), wholegrain and generic health logos (such as Pams's "Pick Me sun" logo).

Analysis

The distribution of the BNI variable was significantly non-normal and some groups were too small in size. The variables did however relate linearly with the dependent variable (BNI). In any case, a non-parametric approach was used for data analysis.
Main analyses: tests of significance (Fisher-Perez's approach) based on sig ≤ 0.05 (ie, results falling within the 5% or more extreme probabilities area), 2-tailed.
Main tests: Mann-Whitney U test for equality of ranked distributions of independent groups, Spearman's rho correlations, and multiple regression on ranked data.
All analyses were carried out with SPSS-v18 (PASW Statistics 18).

Generalization potential

Most yogurts were produced locally or imported and exported from or to Australia, respectively. Thus, the results of this study may be generalizable to the following populations (in order of decreasing generalization power):

Australia.
Internationally, if one assumes breakfast products to be of approximately similar nutritional composition anywhere.

References

1. PEREZGONZALEZ Jose D (2011a). Balanced Nutrition Index™ (BNI™). Journal of Knowledge Advancement & Integration (ISSN 1177-4576), 2011, pages 20-21. Also retrievable from Wiki of Science.

2. PEREZGONZALEZ Jose D (2011b). Yogurts galore. The Balanced Nutrition Index (ISSN 1177-8849), 2012, issue 1.

3. PEREZGONZALEZ Jose D (2011c). Marketing claims and the nutritional balance of yogurt. Journal of Knowledge Advancement & Integration (ISSN 1177-4576), 2012, pages 184-199. Also retrievable from Wiki of Science.

+++ Footnotes +++

4. Namely the Heart Foundation's "Tick" logo as used in New Zealand and, possibly, Australia. Other health-related claims such as wholegrains and Pams's "Pick Me sun" logo, albeit relevant, do not commonly appear on these products.

5. The Mann-Whitney U test uses the sum of ranks for each group and not the medians when testing for statistical significance. However, such sum of ranks is difficult to describe in practice while medians are more straightforward and, thus, preferred. Occasionally, however, apparent contradictory results similar to these may occur.

Want to know more?

BNI™ journal (2012, issue 1) - Yogurts galore: This issue of the Balanced Nutrition Index™ journal collates all BNI™ nutrition information about the original sample in a single book. You can also access information about individual yogurts on the BNI™ database and aggregated information on Wiki of Science (nutritional balance of food).
Wiki of Science - Nutrition topics: This Wiki of Science page provides access to a variety of nutrition topics, including research related to the one summarised above and a related article providing an in-depth description of above results.