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
Tuesday, May 14, 2013
Go to Health: Protect Your GI Tract!
There has been a lot of ‘stomach flu’ in our community this year – actually it is not flu, and is not caused by the influenza virus, which affects the respiratory system. We can call it gastrointestinal disease (the GIs) indicating that it affects the stomach and intestines. The most common cause of the GIs is the norovirus – a group of viruses that cause inflammation of the stomach and large intestine, leading to nausea, vomiting, diarrhea, stomach cramps, low grade fever, headache, muscle aches and fatigue. There is no specific treatment for this disease, but it is vital not to become dehydrated; if you are affected, drink water, diluted fruit juice, and clear soup with some salt or miso. You should recover in 3-4 days, but some cases have lasted longer. Babies and young children can get dehydrated fast – so contact your doctor immediately if your child has serious vomiting and diarrhea. People who are frail or have weakened immune systems should also see their doctor promptly. Prevention of norovirus infection includes avoiding people with the GIs – this virus is highly contagious from handshakes, air droplets, surfaces and food. Wash raw fruits and vegetables carefully. Although the virus is not always destroyed by heat, you should still cook food carefully and completely, and definitely stay away from raw oysters and ceviche if you are determined to avoid getting sick.
Bacterial contamination of food is another serious source of GIs, with resistance to antibiotics a growing problem. Three quarters of antibiotics used in the U.S. are given to animals, not people. They are given to sick animals, and to prevent healthy animals from becoming sick. Antibiotics are also given routinely, to stimulate growth, since animals given low doses of antibiotics grow more quickly on the same amount of food. However, bacteria in the intestines of these animals become resistant to antibiotics, and are excreted in waste. Entering water and soil, they are found on fish, fruits and vegetables. They colonize the GI tracts and skin of farm workers and food processors. They are found in animal meat. They spread to the human population, who may develop antibiotic-resistant infections.
The FDA, the CDC (Centers for Disease Control), and state public-health labs monitor chicken, ground beef and turkey, and pork chops at retail stores nationwide. The percentage of chicken contaminated with salmonella rose to 12% in 2011. More than a quarter of infected samples were resistant to at least five samples of antibiotics.
Here is what you can do: have thoroughly cooked meat and fish when eating out. Forget about medium rare hamburgers unless you are certain the meat is organic. Wash raw vegetables carefully before eating, and know where they were grown, to avoid contamination from nearby factory farming of animals. Avoid fast food restaurants with the exception of Chipotle Mexican Grill, which says it never sells meat from animals treated with antibiotics. Whole Foods makes the same pledge. Niman Ranch, Marin Sun Farms, Applegate organics, Rocky and Rosie chicken and some other companies are also antibiotic free. Organic poultry and meat is less likely to harbor resistant bacteria as organic standards ban meat and fish given antibiotics.
Elderly people in nursing homes are especially vulnerable to illness from antibiotic resistant bacteria. They can benefit – and people of all ages can benefit – from a daily dose of probiotic bacteria. These are healthy bacteria that will colonize your intestines with good organisms which help to fight off the resistant bacteria. Unsweetened yogurt with live cultures can help, but even more beneficial bacteria are found in probiotic capsules, which should be kept refrigerated. We have 3 or more pounds of bacteria in our colons, helping us by digesting fiber and creating important vitamins such as vitamin K and B12. They thrive on the residues of vegetables and fruits, with lots of fiber. These bacteria, and those on our skin, mouth, nose and ears, are called the microbiome. Take care of your microbiome, people!
Sadja Greenwood, MD , MPH