Bitter. It’s such an evocative word—and it’s gotten a bad rap! Did you know that there’s a clear biological reason for our ability to taste bitter? Many plant toxins are extremely bitter compounds. So we developed an evolutionary response to protect us from ingesting spoiled foods and plants that bear poisonous alkaloids, lignans and other potent phytochemicals.
As we evolved to dislike bitter tastes, plants evolved the protective ability to manufacture secondary antifeedant chemicals to defend themselves from being eaten. This production of bitter tasting compounds is carried out regardless of whether the plant actually produces toxin! Essentially, some plants simply mimic their toxic cousins without going to the added effort of producing true poisons. So what is a disgusting taste for us is a clever co-evolutionary survival strategy for plants.
As humans gained more control over our food supply, we followed this aversion to bitterness. We put a heavy emphasis on growing swe
et, carbohydrate-rich grains. For many vegetables, we removed as much bitterness that breeding would allow. There are exceptions, of course. Bitter can still be an acquired taste and the flavor was preserved in a few vegetables like radicchio, dandelion greens and artichokes. Even some varieties of lettuce retain their milky, bitter latex.
More recently, agriculture was coupled with the ability to easily process and distribute foods. The loss of bitterness in our food supply was further exaggerated by ready access to the perfect counter—sugar. So many processed foods have come to include sweeteners that our palate has begun to expect it in just about everything we eat (and we certainly don’t expect bitter). But if our aversion to bitter is a natural, self-protective mechanism to avoid toxic foods, what’s the issue with avoiding bitter tastants?
Remember, producing bitter phytochemicals is a co-evolutionary response by the plants. As it turns out, our evolutionary physical response to bitter extends far beyond a simple aversion to the tastants. Tasting bitter tricks our digestive system into taking a cautious approach to what we’re eating. It challenges our bodies, causing responses that result in secondary, self-protective outcomes. And these bitter plants contain a plethora of phytochemicals that we co-evolved with but rarely eat any longer. Bitter plants may in fact be the ultimate Paleo food, ancient plant chemicals that trigger important biological responses while reminding us on some deep level of our innate primeval heritage.
Dietary bitters have the ability to enhance many aspects of digestion. The bitter taste receptors on our tongue, known as T2R receptors, send messages not only to our brain, but also to our digestive system. Upon tasting bitter, we begin to salivate and traditional wisdom tells us that a cascade of digestive juices are triggered in our stomach, pancreas, small intestine and liver. But science has made new discoveries regarding taste and receptors. We have an estimated 40 to 80 T2R receptors, each able to detect several different types of bitter. And while messaging the bitter taste to our conscious brain stops at the tongue, these receptors are also located in our stomach, pancreatic duct, small intestine, liver and gall bladder. So local messaging continues throughout our digestive tract, reinforcing and augmenting the initial taste response.
That response is complex and frankly, pretty epic! Increased saliva generates enzymes that begin carbohydrate and lipid (fat) digestion. It also produces lysozyme, which has an antiseptic action on our food. Next the stomach secretes hydrochloric acid (HCl) and a precursor that is transformed into pepsin, the enzyme that begins protein digestion. Unlike most enzymes that would not survive exposure to HCl, pepsin requires an acidic environment. Increased stomach acid also denatures proteins and continues the immune work of lysozyme, destroying bacteria and viruses.
Stimulation of the pancreas causes the release of endocrine hormones to modulate blood glucose and pancreatic juices that contain over a dozen enzymes that break down proteins, amino acids, DNA/RNA, triglycerides, sterols and starch. The duodenum releases a hormone that stimulates the gall bladder and peptides that decrease gastric emptying and motility. Enzymes released further down the small intestine continue the digestion of carbohydrates. And the gall bladder releases bile, which is produced by the liver, to emulsify fats that enhance their assimiliation.
There are multiple secondary outcomes from increasing these digestive outputs. As gastric motility and emptying slow, we retain a sense of satiety longer than we normally would. We not only feel full longer, but also faster, so that we end eating sooner. Increases in pancreatic output have a beneficial role in maintaining normal blood sugar. There are strong relationships between the gut’s enteric nervous system and our immunity and mood, as well as the association of our microbiome (gut flora) with immunity. It’s now thought that the health of our microbiome is intimately associated with mind and mood. The role that bitter taste receptors in close proximity to the enteric nervous system play on immunity, brain and mood will continue to be revealed through new research.
Overall, digestion is considered the foundation of health and plays a critical role in immunity, mood and overall well-being. It’s the gateway for all of the nutrients – amino acids, carbohydrates, fats, vitamins and minerals – and all of the phytochemicals from medicinal herbs that feed, nurture and heal our bodies.
Incorporating bitter foods into your diet is an extremely helpful strategy for improving digestion. And adding herbal bitters about 15 minutes before meals is a tasty way to ensure that you are consuming them regularly.