Seed gums in petfood Gums derived from guar, carob, cassia or tara seeds may be found in wet dog and cat food. Those gums furnish galactomannans, carbohydrates composed of chains of mannose units with galactose side groups. The ratio of the two building blocks, which are akin to glucose, is variable. Galactomannans in processed wet, human or pet foods act as thickeners for optimum fluid stickiness and particle distribution. Some dog treats and dry foods contain whole carob seed, also known as locust bean and Saint John's bread, or galactomannan-rich, fenugreek seed. The inclusion levels of single or mixed seed gums in wet petfood range from 0.01 to 0.5%. Adding 0.5% guar gum, as sole thickener, reduces net intestinal uptake of protein in dogs and cats. The indigestible, gel-forming gum interferes with protein digestion. Then, upon reaching the hindgut, guar gum stimulates growth of resident bacteria and water holding, thereby increasing fecal excretion of bacterial protein and water. Mixing 0.5% guar gum into commercial wet food slightly softens and enlarges stool, but does not jeopardize protein supply or intestinal health. A brand of cat food purports that its guar gum constituent reduces blood cholesterol and glucose, and also effectively achieves satiety (1). The gum can lower dogs' blood cholesterol, but there is no known health benefit (2). In dogs, blood glucose after eating was inconsistently influenced by dietary guar gum. In the research literature there is no support for the satiety claim. A few petfoods make a "no guar gum" claim. That implies the gum is bad (3). Guar gum is belittled by stating that it is highly processed, has no nutritional value (4), causes loose stools and impairs protein digestion (5). Only the latter point is valid, but it has no adverse effects at the protein and guar-gum levels in commercial, wet petfoods. Legislation European legislation designates guar, carob and cassia gums as technological additives in feedingstuffs, falling within the subclass of emulsifying and stabilizing agents, thickeners and gelling agents (6-8, Note 1). Guar meal, carob and fenugreek seed are listed in the catalogue of feed materials (9). Galactomannans Seed galactomannans (GM) act as energy storage for germination in the endosperm. Their β-1,4-linked mannan backbones have single galactose units in α-1,6 linkages. The mannose:galactose ratio typifies gums, but also varies within kinds. The ratio is roughly 1 to 5 for GM from fenugreek, guar, tara, carob and cassia seeds. Since galactose imparts hydrophilicity to GM, through inhibiting inter-chain association, water solubility is higher for lower mannose:galactose ratios. To obtain GM-rich gums from seeds, the isolated endosperm is dissolved in water, followed by addition of alcohol as precipitation step. Whole seeds of the five gum sources contain 21-33% GM