Maternal Fruit Intake and Glycemic Index

Longitudinal face-to-face interviews were conducted by trained interviewers three times during the follow-up period: during the first trimester (≤12 weeks), the second trimester (13 to 27 weeks) and the last trimester (≥28 weeks) of gestation. Each subject was asked to complete a 3-day food record (2 weekdays and 1 weekend day), which was reported in a face-to-face interview on the first day and by telephone interview 2 days later. The participants were required to provide information on the types of food they had eaten each day and how much of each type they had eaten. A commonly used portion size was specified for each food type (e.g. a glass, a slice or a unit such as one apple or banana). To reduce measurement error, photographs of normal portions were provided to help the subjects to estimate and record their food consumption in the face-to-face interviews. The types and amounts of food were classified and coded based on the Chinese Food Composition Table40 . The average daily consumption of all fresh fruit items reported by each participant was summed to calculate the total consumption of fresh fruit during the second trimester of pregnancy.
Individual fruits were categorised into three groups based on their GI values: low was defined as GI ≤ 55, moderate as GI > 55 & <70 and high as GI ≥ 70. Because the consumption of fruit in the moderate- and high-GI groups was too small to be analysed separately, fruits with moderate and high GI values were merged into a single group, defined as GI > 5541 . Of the fruit consumed frequently by the participants, apples, pears, oranges, tangerines, grapefruits, peaches/nectarines, apricots, plums and strawberries were defined as low-GI fruit, and bananas, cantaloupes, melons, watermelons, pineapples and lychees were defined as moderate- and high-GI fruit41 . In addition, following Lai et al., the above fruit types were divided into six subgroups according to their polyphenol content using the Phenol-Explorer database. These subgroups comprised pome fruit, citrus fruit, berries, drupe fruit, gourd fruit and tropical fruit (Table 5)17 (link)32 (link). Tropical fruit was defined as fruit cultivated in the tropics, such as bananas, mangoes and persimmons.