Do You Know Nutrition: Light tuna, white tuna - what is the difference?

June 7, 2011 at 1:07 a.m.

By Phylis Canion

Is light tuna better than albacore? Also, for pregnant women, how much tuna is safe to eat because of the mercury content?

Typically, light tuna has less mercury content than white tuna, more commonly known as albacore tuna. Albacore is considered a larger, older and more predator species of fish than the skipjack species, which is typically what light tuna is made from, according to Gavin Gibbons of the National Fisheries Institute.

The older and larger the fish, the more time they have to accumulate methyl mercury through their skin and therefore into the meat. So that you do not turn into the Mad Hatter, light tuna is always recommended.

However, if you are pregnant, studies and recommendations are all over the board as to how much tuna you should or should not eat. My recommendation coincides with a study a few years ago that was published in JAMA, the Journal of the American Medical Association, that recommends pregnant women avoid tuna completely.

You can, however, enjoy other fish that contain low levels of mercury (check them out at, which do provide the body with safe healthy nutrients, such as Omega-3 fatty acids.

Were you wondering what determines the color difference between white and light tuna? That is determined by the Munsell value. Tuna labeled as "light" cannot be darker than a 5.3, according to the Munsell value. Whereas the Munsell value of "white" tuna cannot be darker than 6.3.

And about the Mad Hatter comment? This 180-year-old term came about when dangerous fumes from mercury, used in the making of felt hats, left hat makers suffering with moments of madness from the toxic exposure, hence the term Mad Hatter.

When is it best to wash fruit - as soon as you get home with it from the market or before you eat it?

If you have purchased blueberries, raspberries, strawberries, cherries, plums or grapes, it is best to wash them just prior to eating. These fruits, in particular, have a tendency to absorb odors if they are washed and left to sit, either on your counter or in the fridge. And remember, the best solution to wash your fruits and vegetables with; plain old tap water. Do not fill your sink with water and let your produce sit as the contaminants you wash off just attach to something else - simply hold the produce under the running water and gently rub with your fingers.

Next free nutrition class at Organic Emporium is June 13; call 361-576-2100 today to book your seat.

Phylis B. Canion is a doctor of naturopathic medicine and is a certified nutritional consultant, email her at This column is for nutritional information only and is not intended to treat, diagnose or cure.



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