In brief: Not exactly. Blood actually doesn't get thinned.  what we call blood thinners are agents that decrease the ability of the blood to clot, usually used in people whose blood clots excessively.
Taking B-complex vitamins, which include vitamin B12, can cause urine to have a bright yellow or even orange color, but check with your doctor to be sure that's what is going on in your case. B vitamins are water-soluble vitamins, which means that what your body doesn't use is excreted in your urine. Riboflavin (vitamin B2) is especially likely to cause this color change in urine. Several medications can also turn urine a bright yellow or orange color. Changes in urine color may also signal certain health problems.
Changes in urine colour. A change in your urine colour is normally due to something completely normal, but just occasionally it may be a sign that you should seek medical advice. Urine gets it colour from the pigment urochrome and the colour normally ranges between light yellow and dark amber.aking certain medications can also make the colour of urine change. Vitamin supplements may change the urine to a particularly bright colour. These changes, which are harmless, are due to the pigments and compounds in the food, supplements or medication.