With Lent just around the corner...

All it says is "as observed since 1952" but they don't give any source.

It's a month and a half away, that's pretty close.

At one point, both Eastern and Western Christianity forbade dairy during Lent, so it's a valid question. Now it's just the East.

In some places eggs, milk, butter, cheese and fish are prohibited, while bread, cake, fruit, herbs and vegetables are allowed. In other places, milk, eggs, cheese, butter and fish are permitted, owing either to custom or to Indult. This is the case in the United States. However, in order to form judgments perfectly safe concerning this point, the Lenten regulations of each diocese should be carefully read. Finally, a little tea, coffee, chocolate or such like beverage together with a morsel of bread or a cracker is now allowed in the morning. Strictly speaking, whatever may be classified under the head of liquids may be taken as drink or medicine at any time of the day or night on fasting days. Hence, water, lemonade, soda, water, ginger ale, wine, beer and similar drinks may be taken on fasting days outside meal time even though such beverages may, to some extent, prove nutritious. Coffee, tea, diluted chocolate, electuaries made of sugar, juniper berries, and citron may be taken on fasting days, outside meal time, as medicine by those who find them conducive to health. Honey, milk, soup, broth, oil or anything else having the nature of food, is not allowed under either of the two categories already specified.