“Science is meant to teach us about our world, not remove us from it. Food is meant to nourish us, not merely provide nutrients.“ - Marc David
Early space food was terrible, according to NASA and the astronauts who had to endure it. Most astronauts ate very little on these flights, primarily because the food wasn’t appetizing. Since those early days of space exploration, scientists have learned a good deal about food stability, eating, and digestion in a zero-gravity environment. Although space food is still freeze-dried, dehydrated, and eaten mostly from a pouch, today’s menus have a lot more variety, with around 200 options that range from steak to lasagna, even ice cream. Still, some staples have been on the menu since the early days of space travel, two of which are Tang and, of all things, shrimp cocktail. If this seems like an odd mix, it has a lot to do with how food tastes when traveling in outer space. With the absence of gravity, odors don’t waft into the air and reach the astronaut’s nostrils the way they do on earth, and nasal congestion is more common in microgravity; both factors dull an astronaut’s sense of taste. The pungency of the shrimp cocktail and the “bite” of Tang provides an intense kick that over stimulates the taste buds, making eating a freeze-dried dinner seem more pleasurable.
The astronauts’ preference for spicy foods is an illustration of how eating and food preferences are dependent on much more than nutrients and calories. Eating is a rich, physical experience that engages several of the senses and is influenced by culture, emotions, and personal histories. We may choose a food because of its objective properties, such as its freshness, fiber content, glycemic index, caloric value, or even its cost. But enjoyment and a sense of satiety come from a host of subtle cues—appearance, aroma, mouth feel, crunch, temperature--even our memories can change our experience of a meal. The science of nutrition has grown so rapidly over the past two decades that we frequently approach food clinically, making it a medicine rather than an enjoyable part of the human experience. Our greater sensitivity to nutrition’s role in avoiding chronic disease is invaluable, but we may be losing sight of the larger role food plays in our lives—it nourishes us and can bring us back into balance.
To understand the larger role food plays in our lives, one need not look any further than those who have lost some of their senses to disease or injury. Research is finding that a loss of any of the senses can disrupt our enjoyment of food, making eating problematic. This is why appetite frequently decreases for those who lose their sense of smell due to neurological disorders such as Parkinson’s and dementia, or injuries such as concussions or traumatic brain injuries. Radiation treatments and dental procedures that compromise sense organs in the throat, roof of the mouth, or nasal passages can also dull one’s sense of taste, making food taste bland or metallic. Autoimmune disorders or cancer treatments that damage salivary glands also diminish the enjoyment of food, as taste and flavor are dependent on sufficient salivation; without enough saliva to moisten food is hard to chew, doesn’t coat the tongue sufficiently, and then seems to lack flavor.
Taste is associated primarily with the tongue, which contains thousands of tiny bumps called papillae, each of which contain about 10 to 50 taste receptors. When food is broken down in the mouth, these receptors analyze its chemical composition and then send nerve signals to the brain, where it is perceived as a certain taste. Along with identifying the taste, the brain makes associations with foods and certain emotions, which can add or subtract from our experience of what we eat. It was once thought that the tongue had different zones for various tastes, but we now know that the entire surface is sensitive to all the tastes. Additionally, taste receptors are not isolated to only the tongue; they are found along the roof of the mouth and in the lining of the throat. More recently, receptors for certain tastes, such as sweet, have been found in the colon where they are thought to play a role in glucose regulation.
Taste is not the same as flavor. Whereas taste is a result of what is detected by the receptors on the papillae, flavor is a combination of the food’s odor plus the taste. The proximity of the nose to the mouth helps us detect a food’s odor, as its smell will waft up into the nasal passages. Odors from the food that are released while it is in the mouth can also enter the nasal passages through the nasopharynx, the upper area of the throat behind the nose.
Whereas we can detect between five to six different tastes, our sense of smell can pick up as many as 10,000 different aromas. This is why our sense of smell is so important to the experience of a food’s flavor; studies have found that a food’s odor makes up roughly 75 – 90% of how we experience a particular food. Like taste, smells are coupled with emotions, and since the olfactory centers in the brain are near areas related to memory, smells are quite good at triggering memories—both good and bad-- associated with food. This is nature’s ingenious way of making sure we don’t repeat bad experiences with food. As a child, I became violently ill after eating an egg salad sandwich. Some fifty years later the smell of egg salad still makes me nauseous; I have no interest in repeating that experience again.
The role of taste and flavor in nutrition have been largely ignored in Western medicine. Although this is slowly starting to change, most of the research related to food, eating habits, and health focuses on the role calories, nutrients, and fiber play in disease prevention and weight loss. Nutrition science can provide plenty of guidance about which nutrients we need but is largely silent about the role taste, smell, and our other senses play in how we digest food. For this we need to turn to eastern traditions, such as Ayurveda and Chinese medicine, which, for thousands of years, have provided wisdom on the role taste plays in digestion, providing energy, and maintaining balance in the body.
Western science is still advancing its understanding of the physiology of taste and smell, as well as the neurophysiology of taste and its related emotions, but gives very little attention to the role taste has on the digestive process as a whole. Discussions of diseases that are related to one’s diet, such as irritable bowel syndrome, insulin resistance, and diverticulitis, focus on the process of digestion itself, which begins once food enters our mouth and we start to chew. Eastern healing traditions place greater emphasis on the role taste plays even before food enters the mouth. Ayurveda teaches that different tastes add more than just enjoyment to our foods; they nourish our tissues, impact the entire digestive process as well as our mental state, and have the potential to either create imbalances or restore us to health.
In the west, scientists recognize five different taste receptors. These include sweet, sour, salty, bitter, and savory, which is also called “umami” or “meaty”. Ayurvedic medicine, which is an ancient eastern healing tradition closely aligned with yogic traditions and practices, identifies six tastes: sweet, sour, salty, pungent, astringent, and bitter. Ayurveda believes that digestion begins when a taste is brought to our attention, either physically on the tongue or indirectly by smelling, seeing, hearing, or thinking about a food. The smell of bread baking, the sound of meat sizzling, even the thought of a lemon causes the mouth to water, which gets the digestive juices flowing. The opposite can also be true: seeing a dried-out piece of meat, moldy bread, or something else unappealing can quickly extinguish any desire to eat.
Once food is in the mouth, the process of digestion starts to affect the rest of the body. In Ayurvedic and Chinese medicine, different tastes initiate specific physiological processes. In Ayurveda, sweet, salty, and sour tastes initiate a “building” or calming response in the body; they help us restore our energy, rebuild tissues, and are necessary for growth. Think of how good a bowl of chicken noodle or vegetable soup—with its slight sweetness from the cooked vegetables or noodles and the salt of the broth—helps to restore energy when you are sick. Pungent, astringent, or bitter tastes have a detoxifying and stimulating effect, providing a kick to get us moving. The pungent and bitter taste of black coffee or the astringency of black tea makes these the preferred morning beverages to help start our day.
The building or reducing effects of tastes can be quite noticeable or so subtle that we fail to recognize them. How a taste affects us depends on whether our energy is decreasing and needs to be restored, or if we have a lot of energy that needs to be released. Ayurveda tells us that the discomfort we feel after eating certain foods--heartburn, bloating, brain fog--can frequently be traced to an improper match of a food’s taste to what the body needs at that time. Eating an apple, which causes a drying sensation in the mouth due to its astringency, can create a burning sensation in the stomach if we eat it when our energy is depleted. That same apple can perk us up when it is eaten as a snack intended to give us a boost. Some countries serve a salad of bitter greens after the main course of a meal to stimulate digestion. We may not notice this effect, but it can help overcome the heaviness of the meal. Warm milk sweetened with nutmeg is an Ayurvedic prescription to help calm the nervous system and prepare the body for sleep; that same prescription may make us feel bloated if we drink it very soon after eating a heavy, salty, or overly sweet dinner.
When it comes to food, it is hard for westerners, who are raised to put food into strict measurable categories, to eat according to the more subtle, subjective guidelines proposed in ancient eastern traditions. We prefer the “eat this, not that” approach, thinking of food only in terms of its nutrients; if a food tastes good we somehow believe it must be unhealthy. We have put so many rules on our eating choices that we have lost the ability to simply savor our food, to enjoy the flavors, engage our senses, and nourish ourselves completely. A meal is wedged into our multi-tasking culture; eaten in a car, at a desk, or in front of a screen might provide nutrients but will never satisfy. Maybe that is why so many engage in mindless eating; the Japanese call this Kuchisabishii, or “lonely mouth”, referring to that feeling that you need something more but nothing seems to satisfy.
What I have presented to you in this blog may be hard to wrap your head around, much less put into action. Ayurveda and Chinese Medicine, along with other eastern healing traditions, take years to understand, and then years to master. My intention is to offer a different perspective, an alternative way of approaching that exhausting daily question of “What’s for dinner?”. I invite you to conduct an experiment this week: before you decide what to eat, take a moment to assess your energy level. If you feel depleted, think of foods with sweet, sour, or salty tastes that will help build you up, calm you down, and restore your energy. Keep in mind that these tastes should come from natural foods; many ultra processed foods overuse these three tastes. If you feel a need to erase feelings of sluggishness, consider foods that have light, stimulating flavors, like ginger tea, black eyed peas, basil, dark leafy greens. You can find a list of these foods and more details about the science of Ayurveda at www.Banyanbotanicals.com or by searching “Ayurveda’s Six Tastes”. I hope you enjoy exploring how the tasty side of life can help you find balance—and health—in your body.