DEAR DR. BLONZ: I recently had a good health report, but after starting a new multivitamin -- to up my intake of vitamin D and other essentials -- my urine has become noticeably bright yellow. Is it normal? Does this yellow urine indicate excess bilirubin, or a strain on my liver? -- L.G., Tulsa, Oklahoma
DEAR L.G.: It is pretty standard for specific vitamins to deepen the yellowness of urine, which is typically pale yellow. The B vitamins are not stored in the body, and several of them are yellowish compounds: Vitamin B2 (riboflavin) is known for this effect. Coloring from B vitamins in a basic supplement is not indicative of a strain on the liver, nor of the production of excess bilirubin (a yellowish waste product from the breakdown of hemoglobin).
Check this article on the significance of various urine colors at b.link/3y3ywf.
DEAR DR. BLONZ: I went to a cooking class that included a lecture on oils. The chef explained that when you open a bottle of cooking oil, such as corn, safflower, canola or peanut, it allows air to enter, and that the oxygen in the air begins spoiling the oil. As described in the class, this spoilage is not an immediate health danger, but is an unappreciated hidden cause of disease.
The message was that we must refrigerate all cooking oils after opening. However, I read the labels on bottles of vegetable oil, and they make no mention of any need to refrigerate. -- S.C., Anderson, North Carolina
DEAR S.C.: It is true that air gets in when you open the bottle, and that the oxygen can participate in oxidation reactions associated with spoilage. However, under normal circumstances, it's a slow process, and there is no reason to fear that your oil (or your body, for that matter) is at significant risk.
To safely store oils at room temperature, follow some simple guidelines: Oils should be kept out of direct sunlight and away from heat, and always keep containers sealed when not in use. If you buy more than you will likely use in a few months, split the large size into smaller portions, refrigerating the unused bottles until needed.
There's no problem storing oils in the refrigerator, but if you decide to go that route, be sure the container has a tight seal to keep the oil from picking up any undesirable refrigerator odors. Some oils may become cloudy when refrigerated, but this disappears when they return to room temperature and is no reflection on the oil's wholesomeness.
Oils can go rancid if mistreated or stored in the wrong way. Rancidity occurs when oil reacts with oxygen, and aside from giving foods an "off" taste, the consumption of oxidized oil does represent a health risk. The greater an oil's degree of unsaturation (double bonds), the greater the tendency to oxidize. Omega-3 oils, such as fish oil, have four or five double bonds, making them more susceptible to spoilage as temperatures rise. This helps explain why discarded or unrefrigerated fish soon lends a unique, nasty aroma to a room.
Our body has to deal with unwanted oxidation regularly, and we have a series of systems designed to neutralize these events before they cause any problems. The antioxidants in many whole foods empower this first-alert system. Eating a whole-food, plant-based diet makes it so that we don't have to sweat the small stuff.
Send questions to: "On Nutrition," Ed Blonz, c/o Andrews McMeel Syndication, 1130 Walnut St., Kansas City, MO, 64106. Send email inquiries to firstname.lastname@example.org. Due to the volume of mail, personal replies cannot be provided.