Perceived insufficient milk production (PIM) adversely affects breastfeeding duration. Women sometimes use galactagogues with the intent to increase breast milk production and support lactation. Saccharomyces cerevisiae yeast-based supplement (SCYS) is an inactive form of Saccharomyces cerevisiae yeast (SCY) either obtained from the fermentation process or grown on molasses. Anecdotal evidence suggests SCYS is a galactagogue. SCYS is promoted on the internet as a galactagogue in various forms and doses. Dietary supplementation with SCYS during gestation and lactation significantly increases milk yield in ruminants. No human study has evaluated efficacy of SCYS as a galactagogue. SCYS is rich in B vitamins, beta-glucan, mannan oligosaccharides and bioavailable chromium; these may impact breast milk production or composition, thus may alleviate PIM. The safety of taking SCYS during lactation is not well studied. Studies have reported contamination of SCYS with ochratoxin A (OTA) as well as minor side effects from SCYS. Studies are needed to evaluate the efficacy of SCYS on breast milk production and composition and to assess the safety of taking SCYS during lactation in humans.

Saccharomyces cerevisiae yeast‐based supplements (SCYS) are frequently used as galactagogues with limited evidence of their efficacy. This study investigates the effect of SCYS on human milk oligosaccharide (HMO) concentration and indicators of milk supply. Sixty‐eight breastfeeding women with a healthy singleton infant aged 1–7 months were randomly assigned to consume a SCYS product (5 g/day) or placebo for 4 weeks. The primary outcome was the change in the total HMO concentration. The secondary outcomes included participants' perceptions of milk supply, intervention effectiveness, postnatal distress, infant feeding patterns, infant anthropometry, and adverse effects. Intention‐to‐treat analysis was performed. Multivariable linear regression analysis showed no significant effect of SCYS on individual or total HMO concentrations. However, 65% of women in the SCYS group, compared to 35% in the placebo group, perceived an increase in milk production (p < 0.05). No significant differences were found for other secondary outcomes. However, mothers in the SCYS group had a small but significant improvement in perception of their milk quantity and quality (p < 0.05). SCYS use was also associated with significantly lower formula use at 6 months postpartum (4% vs. 27%, p < 0.05). While SCYS does not impact HMO concentration, it may improve women's perceptions of milk supply. A larger randomised controlled trial is needed to assess its potential effects on actual milk production and composition and address issues of perceived insufficient milk.Trial Registration: This trial was registered at the Australian New Zealand Clinical Trials Registry (trial registration number: ACTRN12619000704190)

Perceived insufficient milk supply (PIM) is the most common reason for breastfeeding women to introduce formula before 6 months postpartum. Anecdotal evidence suggests that galactagogues (substances to enhance breast milk supply) are commonly used in Aotearoa New Zealand. The aim of this study is to investigate galactagogue use and its relationship to mother’s perceptions of their breast milk supply. Breastfeeding women with an infant aged 1–7 months old were invited to complete a survey that included a series of questions to evaluate PIM and other perceptions of their breast milk supply. Participants self-reported the use of galactagogues, including medications, herbs, and supplements as well as special foods. Women were also asked to keep 24 h breastfeeding records. Seventy-two women completed the survey. A total of 64% of the women (n = 46) used galactagogues, with 52% of them (n = 24) using more than one galactagogue. There were no differences between galactagogue users and non-users in terms of maternal age, education, parity, or breastfeeding frequency and total breastfeeding time over 24 h. Frequently used galactagogues were lactation cookies (n = 28), lactation teas (n = 10), and lactation blends (n = 7), and most of them were commercial products. Most of the participants perceived their milk as being in good quality and nutritious and that their infants were satisfied with the amount of breast milk received. However, 18% women (n = 13) reported PIM. Galactagogue use was not associated with PIM or other perceptions of breast milk supply. Interestingly, 59% of the women who thought they had sufficient milk used galactagogues. Galactagogues were widely used regardless of the women’s perceptions of their breast milk supply. Research in a sample including more women reporting PIM is required to understand how galactagogues are used in response to PIM.

Saccharomyces cerevisiae yeast-based supplement (SCYS) is frequently used as a galactagogue. However, its efficacy has only been evaluated in lactating ruminants and sows, not humans. This study aims to investigate the effect of taking an SCYS on human milk oligosaccharide (HMO) concentration and perceived insufficient milk supply (PIM). A randomized, double-blind, placebo-controlled trial was conducted at Palmerston North, New Zealand from May 2019–July 2021. Breastfeeding women with a term infant aged 1–7 months were randomly assigned to consume an SCYS (5 g/day) or placebo for four weeks. Concentration of 11 HMOs were analyzed by UHPLC with fluorescence detection. Online questionnaires were used to evaluate PIM, postnatal distress, infant feeding status, and self-reported side effects of taking SCYS. In addition, the infants’ feeding pattern (duration and frequency of breastfeed) were examined using a 24-hour feeding record. Sixty-eight women completed this study. The SCYS had no effect on individual or total HMO concentration. There were no significant differences in PIM, postnatal distress, or infant feeding pattern between the SCYS and placebo groups. However, more participants in the SCYS group than the placebo group perceived that the intervention increased their milk supply (65% vs. 35%, p < 0.05). Women in both groups reported adverse effects, but no participant withdrew from this study. The SCYS has no effect on HMO concentration or PIM. Research is needed to investigate the effect of SCYS on breast milk volume and self-reported indicators of milk supply increase.

Human milk oligosaccharides (HMOs) are the third most abundant component in breast milk. HMOs benefit infant gut health, modulate immune responses, and promote brain development. The profile and concentration of HMOs vary considerably among breastfeeding women, and are reported to be associated with genetic, maternal, and environmental factors as well as feeding practices. One reason for the diversity in HMO concentration is the secretor gene, which determines the presence of an enzyme responsible for the synthesis of 2′-FL and LNFP-I. To date, there is no report about HMO concentration or profile in the New Zealand population. Our objective was to investigate 12 HMO concentrations in a small sample of New Zealand women. Sixty-eight breastfeeding mothers (mean age 32 years, 77% Caucasian) of singleton infants (median age [Q1, Q3] 108 [70, 166] days) were included, with 65% exclusively breastfeeding and 54% who had two or more children. Concentrations of 12 HMOs were measured by UHPLC with fluorescence detection. Overall, 68% of mothers were secretors, which was defined by the presence of 2′-FL in the milk. HMO profiles varied widely; total HMO concentration varied 4.2-fold between women; and individual HMOs varied from 4.8-fold to >100-fold. The median of total HMO concentration (Q1, Q3) of the secretors and non-secretors were 6774.9 (6395.4, 8245.6) mg/L and 7128.0 (6093.1, 7880.1) mg/L respectively. Significant differences in concentration of 2′-FL, 3-FL, A-Tet, LNFP-I, LNFP-II, LNFPV, and LNnT between secretors and non-secretors were found by Mann–Whitney tests. However, there was no significant difference in concentrations of LNFP-III, LNnFP, 3′-SL, 6′-SL, LNT, or total HMOs between the secretors and the non-secretors. HMO concentrations vary broadly between breastfeeding women. A longitudinal cohort of a larger sample size is required to fully investigate HMO profiles at different lactation stages of New Zealand women and to further explore the influence of maternal and environmental factors on HMO concentration.