Nutrition claims and the BNI of yogurts - 2011

---

Data

[PEREZGONZALEZ Jose D (2011). Nutrition claims and the BNI of yogurts. Journal of Knowledge Advancement & Integration (ISSN 1177-4576), 2012, pages 228-230.] [Printer friendly] [YouTube channel] [Screenr channel]

Nutrition claims and the BNI of yogurts

Nutrition 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 three nutritional claims appearing on yogurts: low sugar, low fat and high fiber⁴. The results seem to support several main inferences. Firstly, regarding yogurts with 'high fiber' claims, that yogurts with such claims have an average BNI lower (median = 76.93) than other yogurts (median = 90.50), that such difference is also found between groups (U = 480, p < 0.01) and that the corresponding correlation indicates a trend between sporting a fiber claim and lower nutritional unbalance (rho = -0.225, p < 0.01). Secondly, regarding yogurts with 'low fat' claims, that yogurts with such claims have an average BNI lower (median = 89.62) than other yogurts (median = 96.76), and group differences and correlation are also statistically significant. And thirdly, that yogurts with 'low sugar' claims also have a BNI lower than other yogurts, although this inference may seem contradictory given that the median of yogurts with 'low sugar' claims (= 92.19) is higher than that of other yogurts (= 90.50) (which is due to a discrepancy when reporting results⁵, see Perezgonzalez, 2011c³ for more information in this regards). In any case, even when statistically significant, differences in medians and correlations for low sugar and low fat claims are rather small, and they may not be that important in practical terms.

Illustration 1: Nutrition claims on yogurts
Claim »	Low sugar		Low fat		High fiber
BNI	No	Yes	No	Yes	No	Yes
0	0	0	0	0	0	0
<10	0	0	0	0	0	0
<20	0	0	0	0	0	0
<30	0	0	0	0	0	0
<40	2	0	1	1	1	1
<50	0	0	0	0	0	0
<60	5	1	2	4	6	0
<70	12	22	8	26	30	4
<80	22	1	1	22	21	2
<90	85	0	4	81	84	1
<100	83	18	44	57	99	2
<110	49	7	26	30	55	1
<120	24	0	2	22	24	0
<130	9	0	5	4	9	0
<140	2	0	2	0	2	0
Median	90.505	92.195	96.76	89.62	90.50	76.93
U (p)	4982.05	( .000 )	8355.5	( .000 )	480.0	( .000 )
rho (p)	-.186	( .000 )	-.223	( .000 )	-.225	( .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 nutrition-related claims such as high-fiber, low-fat, low-sugar and low-sodium.

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

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. Low-sodium claims, 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.

---

Did you understand?

+ Test yourself

• 1- It is better to choose yogurts with low fat and low sugar claims.
  • a- Yes, but it is only marginally better.¹
  • b- No, it is better to avoid yogurts with a low sugar claim.²
  • c- No, it is better to choose yogurts with a low sodium claim.³

Test answers

1. True.

2. False. Actually, it is better to choose yogurts with a low sugar claim, although only marginally so.

3. False. Perhaps it is true, but such claim does not commonly appear on yogurts.

---

Author

Jose D PEREZGONZALEZ (2012). Massey University, Turitea Campus, Private Bag 11-222, Palmerston North 4442, New Zealand. (JDPerezgonzalez).

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.

---

Other interesting sites

Knowledge

WikiofScience

AviationKnowledge

A4art

The Balanced Nutrition Index