Friday, May 24, 2013

Umami – The Fifth Taste

Why are Claire Heart’s soups at the Bolinas People’s Store so delicious? It’s partly the mystery of a great cook, but another reason is that she uses fresh organic ingredients, and makes sure that all the tastes on our taste buds are stimulated. (Maybe with the exclusion of bitter, although people who like coffee and beer, or flavor foods with citrus peel, are enjoying the mild taste of bitter.) We have taste buds on the tip of our tongues, where you can actually see them as tiny bumps; they are also located all over the tongue, the mouth and the throat. Each taste bud has receptor cells for sweetness, sourness, saltiness, bitterness and umami. Umami taste is described as savory and brothy. Except for the bitter taste, great cooks like Claire add just the right amount of each flavor. Coconut milk often adds to the mixture, giving a wonderful fragrance and the smooth mouth feel of fat. Flavors beyond the basic five are detected by our sense of smell.

Umami is a transliteration of the Japanese word for a pleasant, savory taste. The receptors for umami are not the same as those for salt – umami receptors on the tongue respond to the amino acid L-glutamate. To get a first hand experience, chew a very ripe tomato (try a sun-dried one at this time of year), taste the flavor carefully, and feel the sensation in your mouth and cheeks. You’ll taste sweet and sour, and also umami.

Here’s a bit of biochemistry: glutamate is the most abundant excitatory neurotransmitter in the human nervous system. It is involved with learning and memory. When sensitive people ingest too much glutamate, in the form of MSG (monosodium glutamate), they can develop headache, tightness in the face and jaw, heart irregularities, and even seizures. Most restaurants stopped using MSG in the 1990’s because of publicity about these problems, and customer complaints; they were adding it to food because it enhanced the taste so much.

Umami found in natural foods will enhance taste but will not cause harm.

Most humans’ first taste of umami comes in mother’s milk; we learn to like it early! Foods high in the umami taste include kombu, nori, fish and shellfish, mushrooms, ripe tomatoes, green tea, soy beans, sweet potatoes, Chinese cabbage, carrots, and cheeses. Using these foods to enhance your home-made meals will bring you pleasure and good health. Eat cheese sparingly for flavor – it is high in saturated fat and salt.

The FDA has stated that MSG is ‘Generally Recognized As Safe’, but requires that the words ‘monosodium glutamate ‘ be written on the label if it has been added to the food. However, there is a significant amount of controversy about other additives found in processed foods and fast food restaurants. These additives contain free glutamic acid but are not MSG; hydrolyzed vegetable protein, hydrolyzed soy protein, yeast extract and autolyzed yeast are examples. They impart an umami flavor to food. It is difficult to know if there is a valid concern about eating small amounts of these substances. However, the more we know about the way packaged and processed foods are designed to increase your wish to overeat them, the less desirable they seem. Too much fat, sugar, salt are causing health problems that are easily avoided by the thoughtful eater.

Eden Foods: Here’s a sad and controversial new development. Eden

Foods is suing the Obama Administration over its mandate to cover birth control under the Affordable Care Act. Michael Potter, the company’s owner and CEO, claims that his religious beliefs are being violated by requiring him to pay for healthcare services, including contraception. You may know that Eden Foods is a pioneer in using cans that are free of Bisphenol A, and has many excellent organic products. The lawsuit has caused a good deal of controversy among groups supportive of reproductive rights. Some are choosing to boycott Eden products. Stay tuned.

Sadja Greenwood, MD, MPH

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