Trigonelline is a bitter alkaloid found in coffee that contributes to its aroma. The concentration of trigonelline is higher in arabica coffee than in robusta, ranging from about 0.6-1.3% and 0.3-0.9%, respectively. During the roasting process, trigonelline partially degrades to produce two important compounds - pyridines and nicotinic acid (also known as vitamin B3 or niacin). This means that a very dark roast will contain only a fraction of its original trigonelline content.
Interestingly, coffee has been found to contain a significant amount of niacin, providing 10-40mg of niacin per 100g of coffee, which far exceeds the daily recommended dosage. Decaffeinated coffees typically contain about 35% less nicotinic acid due to the elimination of trigonelline by chlorinated solvents.
In addition to its role in coffee, trigonelline has been found to reduce the incidence of dental caries due to its ability to prevent Streptococcus mutans, a type of bacteria, from adhering to tooth enamel
Trigonelline is found in fenugreek (Trigonella foenum-graecum) seeds, which have been used in various regions worldwide as a galactagogue to increase milk supply. The galactogogue effect of fenugreek may be primarily psychological in humans; however, animal studies indicate that fenugreek might work primarily by increasing insulin and oxytocin secretion. Evidence for a galactogogue effect is mostly anecdotal. A limited number of published studies of low to moderate quality have found mixed results for a galactogogue effect for fenugreek. In a US survey, of 122 mothers who used fenugreek as a galactogogue, 43% thought it increased milk supply and 5% thought it decreased their milk supply. Some evidence indicates that fenugreek might be more effective in the first few days postpartum than after 2 weeks postpartum Source.
One study found that trigonelline, a compound found in coffee, has a galactagogue effect in rats, meaning it could potentially increase milk production. However, this effect has not been conclusively demonstrated in humans. It's important to note that the effects of substances can vary greatly between species, and what works in rats may not work in humans. Moreover, the concentration of trigonelline in coffee may not be sufficient to have a significant effect on milk production.
It's important to note that the use of galactogogues should never replace evaluation and counseling on modifiable factors that affect milk production. Also, fenugreek is generally recognized as safe by the U.S. Food and Drug Administration, but it can cause gastrointestinal side effects such as nausea, vomiting, diarrhea, and flatulence. It's always best to consult with a healthcare provider before starting any new supplement or medication.