Detection of Volatile Metabolites of Garlic in Human Breast Milk

Abstract

The odor of human breast milk after ingestion of raw garlic at food-relevant concentrations by breastfeeding mothers was investigated for the first time chemo-analytically using gas chromatography−mass spectrometry/olfactometry (GC-MS/O), as well as sensorially using a trained human sensory panel. Sensory evaluation revealed a clear garlic/cabbage-like odor that appeared in breast milk about 2.5 h after consumption of garlic. GC-MS/O analyses confirmed the occurrence of garlic-derived metabolites in breast milk, namely allyl methyl sulfide (AMS), allyl methyl sulfoxide (AMSO) and allyl methyl sulfone (AMSO2). Of these, only AMS had a garlic-like odor whereas the other two metabolites were odorless. This demonstrates that the odor change in human milk is not related to a direct transfer of garlic odorants, as is currently believed, but rather derives from a single metabolite. The formation of these metabolites is not fully understood, but AMSO and AMSO2 are most likely formed by the oxidation of AMS in the human body. The excretion rates of these metabolites into breast milk were strongly time-dependent with large inter-individual differences.

Detection of Volatile Metabolites Derived from Garlic (Allium sativum) in Human Urine

“…In contrast, the derivatives AMSO and AMSO 2 are reported here for the first time as garlic-derived compounds in human urine, demonstrating that constituents of garlic are heavily metabolized prior to their excretion via urine. It is also interesting to note that AMS, AMSO and AMSO 2 have previously been reported as garlic-derived constituents in human milk by our group [22], indicating that there are similar pathways for the excretion of such substances via different bodily fluids. …”

“…Changes in the odor of bodily fluids may indicate the presence of volatile constituents or metabolites of food components [22,23,25]. Pre-trials indicated that slight odor changes, relating to the attribute “garlic-/cabbage-like”, were observable in human urine after garlic consumption; accordingly, this attribute was rated by the panelists in the different urine samples on a scale from 0 (no perception) to 3 (strong perception).…”

“…The obtained chromatograms were compared and matched with their respective control samples, so that additional peaks in the urine extracts resulting from garlic intervention could be elaborated. Additionally, a targeted search was carried out for those substances that have either been reported to be present in garlic itself or have been previously proposed as metabolites [22,29,36,37,38,39,40]. This target substance selection is shown in Table 2, together with the RIs and m / z ratios used for data extraction.…”

“…Potential physiological effects in relation to food or beverages are often investigated on substances that occur naturally in the product, but potential metabolism within the body is rarely considered. In view of this, recent research has shown that volatile substances can undergo major transformation steps within the body or can be released from non-volatile precursors, e.g., in the human gastrointestinal tract [20] or during absorption processes [21], leading to compounds that were not present in the original product [22,23,24,25]. …”

Complementary Feeding Strategies to Facilitate Acceptance of Fruits and Vegetables: A Narrative Review of the Literature

“…Breast milk flavors may vary from one feeding episode to another [14,15]. Formula flavors may also differ according to their types, whether they are regular, antiallergic (with hydrolyzed protein), antidiarrheic, fermented, etc.…”