DEAR DR. BLONZ: Does vegetable oil mellow or otherwise improve with age? We have a number of bottles that we received as gifts but they have been sitting on the shelf for about a year and a half. They were in such beautiful bottles that nobody wanted to open them. Are they still ok to use if they have not been opened? -- J.L., Glendale, Ariz.
DEAR J.L.: Unlike wine, oils do not improve in the bottle. An extra virgin olive oil, for example, will be at its best when first put in the bottle (or can) and it's all downhill from there. Oils should be tightly covered and stored away from heat and light. An unopened container of refined vegetable oil that is properly stored can maintain its quality for about a year. Some oils, including extra virgin olive oils, claim they can last up to two years unopened. After being opened, if stored properly, you have about six months with most oils.
As a general rule, the more unsaturated the oil, the shorter the shelf life. Oils that have been sitting for questionable periods of time should get a sniff and a taste test before being used.
It is always best to buy your oil in containers that match your expected rate of use. If you end up buying in large containers, consider splitting the contents and putting half in the refrigerator for later. Select a container size that allows for very little air space atop the oil as it is stored. To help you keep track, mark the date of purchase, and the date the container was opened, on the label.
DEAR DR. BLONZ: What is taurine? I saw it listed as an ingredient in cat food and didn't give it much thought. Now I find that it is an ingredient in some of those energy drinks. I don't know what it is or what it is supposed to do, and was hoping that you could help. -- R.G., Bend, Ore.
DEAR R.G.: Taurine is a common amino acid, one of the building blocks of protein. Although needed by cats, it is not an essential amino acid for healthy human adults in that the body can make all that it needs. In addition, there are plentiful amounts in meats and fish. There is, however, some preliminary evidence that taurine at higher levels of intake may be of therapeutic value for those suffering from congestive heart failure. It is unclear what taurine adds to energy drinks, especially given the small amounts present in such beverages.
Send questions to: "On Nutrition," Ed Blonz, c/o Universal Uclick, 1130 Walnut St., Kansas City, MO, 64106. Send email inquiries to email@example.com. Due to the volume of mail, personal replies cannot be provided.