Kiwifruit may help manage blood sugar levels and provide nutrients. Clinical trials showed: 1) Eating kiwifruit with or before carbohydrates reduced blood sugar spikes compared to carbohydrates alone. 2) Partially substituting kiwifruit for starchy foods like bread or rice lowered the overall rise in blood sugar. 3) Kiwifruit exchanges in meals did not increase hunger and provided vitamins, minerals, and fiber. Next steps are longer trials examining kiwifruit's effects on diabetes risks, metabolism, and cardiovascular health.

1. Kiwifruit - A Double Agent for Glycaemic
Control and Nutrient Enhancement
Dr John Monro
Plant & Food Research, New Zealand

2. Acknowledgements
• Zespri
• Carbohydrate Digestion and Metabolism Team,
Plant & Food Research:
– Kerry Bently-Hewitt
– Sue Middlemiss-Krak
– Suman Mishra
• Jinny Willis, Don Bevan Centre, Christchurch
• All participants in the clinical trials

3. Plan of talk
• Measuring the properties of kiwifruit that could be beneficial
• Testing the role of kiwifruit properties in clinical trials
• Measuring the glycaemic potency of kiwifruit
• Exchanging kiwifruit for other carbohydrate foods – glycaemic
and nutritional consequences
• Next steps – the HVN/Zespri phase

4. Aim
• Help Zespri to sell kiwifruit in an increasingly diabetic, sugar averse
market, by showing that they are safe and healthy
• HVN $1 million over 3 years
• Zespri $100,000 over 3 years
Project funding

5. Problems and possibilities for kiwifruit
Market is becoming fearful
of sugars
Kiwifruit are sugar-rich
Kiwifruit sugars are about
50% fructose (fruit sugar) -
fructose is bad news
+- Kiwifruit are a rich source
of vitamin C
Kiwifruit may aid digestion
Kiwifruit appear to stimulate
laxation
Used the right way, kiwifruit
may reduce glycaemia and
protect against its effects
-
-
+
+
+

6. >400 million
diabetic by 2030
A problem and opportunity facing
the kiwifruit industry
• A “tsunami of diabetes”
in the major markets
for kiwifruit
Best quality
kiwifruit
> 400 million
diabetic by
2030
Best quality
kiwifruit

7. Challenges
• Showing that kiwifruit, even in the diets of consumers at risk for
diabetes, are nutritionally beneficial
– Short term (postprandial)
– Long term (metabolic and diverse diabetic complications)
• Incorporating kiwifruit into the diet in ways that lead to a net health
benefit to consumers

8. Kiwifruit have favourable properties
2 kiwifruit
↓
900 ml disperse
hydrated solids volume
Stomach is distensible
50 (empty)-1500 ml
Therefore dietary fibre dispersion from
one or two kiwifruit, easily fills gastric
space surrounding and interacting with
other foods.
Kiwifruit settled bed volume increased about 4x after digestion
Residues occupied a large volume after digestion
Post-digestion volume per unit of
pulp digested and settled overnight

9. Reduced rate of glucose absorption in vivo?
Luminal mixingLuminal diffusionDigestion
Altered postprandial blood glucose response?
Disperse kiwifruit cell wall remnants retarded processes involved in
glycaemic response

10. Wheat biscuit + 2 kiwifruit (WB+KF), compared with
Wheat biscuit + 2 kiwifruit’s sugars (WB+Sug) (n = 20)
Non-carbohydrate components of kiwifruit moderated glycaemic
response in vivo
• Reduced amplitude
• Sustained availability
• No hypoglycaemia
Means ± sem
Conclusion: Non-carbohydrate components
of kiwifruit may improve glucose homeostasis

11. Equal carbohydrate partial substitution of kiwifruit for starchy food
reduced glycaemic response
Mean blood glucose responses to
equal (40 g) available carbohydrate
meals:
Glucose
Wheat biscuit (WB),
WB + ‘Hayward’ kiwifruit (WB+GR)
WB + SunGold kiwifruit (WB+SG)
Recommended limit
Incorporating KF into a diet without increasing carbohydrate
or energy intake – the dietetic approach
Benefits confirmed

12. Areas within measurement periods showed
improved glucose homeostasis
0-180 min: (full period) LSD 26.8, p = 0.012,
0-120 min: LSD = 22.7, p <.001
120-180 min LSD = 11.5, p < 0.001
SunGold and Hayward improved glycaemic response over 3 h.

13. Relative glycaemic potency (RGP)
Allows the glycaemic potency of a food to be expressed as grams of glucose
equivalents (GGE) per 100 g food. The glycaemic effects of SunGold and
Hayward were measured relative to a 40 g glucose reference.
IAUCfood/IAUCgluc x WtGluc/Wtfood x 100
= RGP (g glucose equivts./100 g)
= GGE/100 g

14. Kiwifruit has a low relative glycaemic potency (GGE/100 g)
(Means ± sem) (LSD = 4.9, p < 0.001)
GGE per 100 g food
One kiwifruit had the same effect on blood glucose as 6.6 g glucose

15. Relative glycaemic impact expressed as a virtual
food component (GGE (g) /given quantity)
GGE per serving
Relative glycaemic impact can
be expressed in gram units, so
behaves like a nutrient.
Because it is expressed as if it
were a nutrient, but represents
an effect, it has been termed a
virtual food component.

16. Kiwifruit Serving size – 100 g (Approx) Per serving PER 100 g
Energy-kJ
Protein (g)
Fat (g)
Carbohydrate
- Total
- Sugars
Dietary fibre (g)
Sodium (mg)
Potassium (mg)
Vitamin C (mg)
Β-carotene equiv. (µg)
Glycaemic impact (glucose equiv.) (g)
202
0.9
0.6
11
10
2.3
4
236
120
18
6
202
0.9
0.6
11
10
2.3
4
236
120
18
6
Relative glycaemic impact: LOW
Potential role of GGE in showing relative
glycaemic impact in food labels

17. Effect of equi-carbohydrate substitution by
kiwifruit on estimated GGE dose.
Kiwifruit exchanges
Serve GI CHOAVL GGE Exchange 1 KF Exchange 2 KF
(g) (%) (g/serve) (g) New GGE % Decr New GGE % Decr
Bread white 60 75 30 22.5 18.9 16 15.3 32
Cornflakes 30 80 25 20.0 15.8 21 11.5 43
Rice Bubbles 30 88 26 22.9 17.6 23 12.4 46
Rice, white (China) 150 83 36 29.9 25.3 15 20.6 31
Rice, Jasmine (Japan) 150 109 42 45.8 37.9 17 30.0 34
Rice, Japonica (Japan) 150 75 46 34.5 30.9 11 27.3 21
Mashed potato (China) 150 73 20 14.6 11.2 23 7.9 46
Sweet potato (China) 150 77 21 16.2 12.3 24 8.4 48
1 Kiwifruit 100 46 12.5 5.8 5.8 0 5.8 0
2 Kiwifruit 200 46 25 11.5 11.5 0 11.5 0

18. Equal carbohydrate, partial exchange of whole kiwifruit
for starchy staple improves nutrient intake
Effect of partially replacing the
available carbohydrate in
starchy staple foods by the
amount of available
carbohydrate in one whole
kiwifruit.

19. Timing of kiwifruit ingestion relative to
carbohydrate food may be important
SunGold kiwifruit consumed 30 min before wheat biscuit
(WB) decapitated the blood glucose spike
WB alone WB + SG together WB 30m post SG
(40% less than WB)
Equi-carbohydrate comparison

20. Kiwifruit has a role in appetite control during
glycaemia management
Kiwifruit-substituted Wheat Biscuit was as satiating as Wheat Biscuit
alone at the same CHO intake

21. Next steps: The HVN-Zespri phase
• Consumer safety: Insulin response, fructose effects
• Customary food consumption: Realistic meals, customary diets
• Plausable mechanisms: Metabolic, hormonal, pancreatic, physiological-metabolic syndrome
• Relevant endpoints: CVD, circulatory, β-cell function
• Relevant biomarkers: Plasma lipids, glycation, oxidative stress, inflammation, endothelial dysfunction
When to eat kiwifruit: clinical
Kiwifruit exchanges in realistic
European and Asian meals
(postprandial)
(2016)
Kiwifruit exchange tables
(2016)
Metabolic effects of
long-term
KF consumption
(KRIP pilot study)
(2016)
Long-term consumption
metabolic effects
(healthy)
(2017)
Long-term consumption
metabolic and risk factor effects
(prediabetic)
(2018)
Intake patterns for
optimal effect
HVN