Center for Alaska Native Health Research, Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK, United States; Department of Biology and Wildlife, University of Alaska Fairbanks, Fairbanks, AK, United States.
Gertner Institute for Epidemiology and Health Policy Research, Sheba Medical Center, Tel Hashomer, Israel.
Am J Clin Nutr. 2024 Sep;120(3):630-637. doi: 10.1016/j.ajcnut.2024.05.007. Epub 2024 Aug 6.
The breath carbon isotope ratio (CIR) was recently identified as a noninvasive candidate biomarker of short-term added sugars (AS) intake.
This study aimed to better understand the potential of the breath CIR as a dietary biomarker. We evaluated the effects of short-term and long-term intakes of AS, animal protein (AP), and related variables on breath CIR, in the context of typical dietary intake patterns.
We conducted a 15-d controlled feeding study of 100 adults (age 18-70 y, 55% females) in Phoenix, AZ. Participants were provided individualized diets that approximated habitual food intakes and recorded the timing of food consumption. Three breath samples (fasting, midday, and evening) were collected on each of 3 nonconsecutive study days. We modeled the effects of dietary intake in each of 8 h preceding collection of the breath sample on breath CIR with a linear mixed model, which also included 15-d mean intakes, sex, age, and BMI.
Median (IQR) intakes of AS and AP in our study were 65 (38) and 67 (33) g/d, respectively. Midday and evening breath CIRs correlated strongly with each other (0.80) and with fasting breath CIR (0.77 and 0.68, respectively). In our linear mixed models, breath CIR increased by AS consumed 1-4 h before sample collection, AP consumed 3-6 h before sample collection, and 15-d intakes of AS and AP, all with similar effect sizes. The breath CIR was also inversely associated with 15-d intakes of intrinsic sugars and plant protein; thus, associations with 15-d intakes were particularly strong when expressed proportionally as the AS ratio (added sugars/total sugars) and AP ratio (animal protein/total protein).
The breath CIR is a promising measure of long-term intakes of AS and AP, especially as proportional intakes. Approaches to increase specificity would benefit the further development of this biomarker.
呼吸碳同位素比（CIR）最近被确定为短期添加糖（AS）摄入量的非侵入性候选生物标志物。
本研究旨在更好地了解呼吸 CIR 作为饮食生物标志物的潜力。我们评估了短期和长期摄入 AS、动物蛋白（AP）和相关变量对呼吸 CIR 的影响，同时考虑了典型的饮食摄入模式。
我们在亚利桑那州凤凰城进行了一项为期 15 天的对照喂养研究，共有 100 名成年人（年龄 18-70 岁，55%为女性）参与。参与者接受了个性化的饮食，这些饮食接近习惯性食物摄入量，并记录了食物摄入的时间。在 3 个非连续研究日中的每个研究日采集 3 个呼吸样本（空腹、中午和晚上）。我们使用线性混合模型，根据收集呼吸样本前 8 小时的饮食摄入情况，对每个呼吸样本的 CIR 进行建模，该模型还包括 15 天的平均摄入量、性别、年龄和 BMI。
在我们的研究中，AS 和 AP 的中位数（IQR）摄入量分别为 65（38）和 67（33）g/d。中午和晚上的呼吸 CIR 彼此之间以及与空腹呼吸 CIR 之间相关性很强（0.80、0.77 和 0.68）。在我们的线性混合模型中，呼吸 CIR 随着样本采集前 1-4 小时消耗的 AS、样本采集前 3-6 小时消耗的 AP 以及 15 天的 AS 和 AP 摄入量而增加，这些效果的大小相似。呼吸 CIR 还与 15 天的内源性糖和植物蛋白摄入量呈负相关；因此，当以 AS 比（添加糖/总糖）和 AP 比（动物蛋白/总蛋白）的比例表示时，与 15 天的摄入量的关联特别强烈。
呼吸 CIR 是一种有前途的长期摄入 AS 和 AP 的测量方法，特别是作为比例摄入。增加特异性的方法将有益于该生物标志物的进一步发展。
