DEAR DR. BLONZ: I enjoy making tuna salad sandwiches, but wanted to know about the different types of tuna. Does canned tuna packed in oil have higher levels of omega-3 fat than tuna packed in water? -- M.M., Hayward, California
DEAR M.M.: With few exceptions, the oil used for canned tuna is either soybean or canola oil, not fish oil. As a result, the oil-pack contains extra fat, but little in the way of extra amounts of the healthful omega-3 fats. A 3.5-ounce serving of light tuna in water (drained) contains 0.8 grams of fat and 0.3 grams of omega-3 fats. Contrast this with light tuna in oil (drained), which contains 8.2 grams of fat and 0.2 grams of omega-3 fats.
For more of the omega-3 fats, consider using the albacore (white) tuna. A 3.5-ounce serving of water-packed albacore contains about 3 grams of fat, of which 1 gram is omega-3. This is due to the fact that light tuna is made from the yellowfin and skipjack varieties, and these contain less of the omega-3 fatty acids than albacore.
For more issues relating to tuna, including a brief discussion of mercury, sodium and ecological concerns relating to how the fish are caught, check out the article at goo.gl/RyzX8u.
DEAR DR. BLONZ: I am all about avoiding partially hydrogenated oils and trans fats, but what about “fractionated vegetable oils”? What does “fractionated” mean? I’ve come across the ingredient several times, most recently in a “soy chocolate peanut” protein bar. -- L.S., San Diego
DEAR L.S.: Fractionation is a process by which fats and oils are separated into various fractions, often based on melting characteristics. It is a preferable alternative to partial hydrogenation because it does not lead to the formation of trans fatty acids. One example of the use of fractionated vegetable oil might be as an ingredient in a coating or frosting. In this case, manufacturers have an interest in selecting the “fraction” of the oil that works best to help the product remain solid at room temperature.
DEAR DR. BLONZ: I have been taking Coumadin for about a year now, as prescribed by a Kaiser clinic. I recently had an episode of internal bleeding and needed surgery. I am recovering, and they want me to begin taking the Coumadin again. To your knowledge, are there any studies that differentiate Coumadin from other blood thinners? Are there any natural dietary supplements I might take to act as blood-thinner agents? -- K., Richmond, California
DEAR K.: As I am not a medical doctor, I cannot offer medical advice, and that is what you need. The health professionals at Kaiser should be able to discuss the advantages/disadvantages of various anticoagulant medications. I would strongly advise against any reliance on dietary supplements for this purpose. That being said, it is essential that you inform your health care team of any dietary supplements you take.
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.