According to some researchers, the color of urine matches hydration levels in humans [1]. Therefore, it has been proposed that urine color could be used to determine our individual hydration levels. So what color should urine be?

Recommendations for the color we should aim for seem to range from clear urine, to pale yellow, to straw-colored.

But who is right and what is actually healthy? This question could be relevant to those of us who suffer from bladder problems, especially overactive bladder (OAB).

The urine colour chart

The researchers Armstrong et al have formulated the ‘urine color chart’ with 8 different shades of yellow.

According to a recent analysis [1], these colors match fluid intake – the higher the fluid intake, the paler the urine.

Everyone, from official health guidelines to your average fitness or wellness guru, seems to be obsessed with adequate hydration these days. Accordingly, the usual recommendation in relation to the urine chart looks like this:

Notice that clear urine is usually deemed to indicate good hydration levels and that the broad spectrum of colored urine is supposed to indicate dehydration.

Potential problems with the urine colour chart

To determine hydration level, the color of urine was checked against urine volume and specific gravity (a measurement for urine concentration).

However, the report does not set a specific gravity that we should aim for. It only mentions that recommendations for patients with recurrent kidney stones would be below 1.010 and that dehydrated elderly people often have a specific gravity of 1.017 [1].

A different recent study on hydration reported a specific gravity of 1.016 for properly hydrated (euhydrated) women and 1.018 for euhydrated men [2].

There seems to be no set conclusion of a target specific gravity and therefore it would be hard to define the target urine color that corresponds to it.

The urine color chart also has mainly been studied for acute dehydration and ‘sedentary adults in normal daily living conditions’ [1], so it may not be relevant for everybody.

In fact, urine color does not seem to correspond well to hydration status in the elderly [1].

So basically what this tells us is that urine color becomes clearer when urine is diluted and darker yellow when it is more concentrated. It doesn’t really tell us which is best.

Also, once urine is diluted and clear we would not be able to determine further dilution – with the potential of over-hydration.

 

The ideal urine colour

Because most of us are following ‘official’ guidelines on how much fluid to consume, plus our social life is very much centered on beverages (alcohol, coffee, tea and so forth) it is hard to know what natural human urine is supposed to even look like…

Therefore I always like to take look at animals – because they usually just follow their instincts/hunger/thirst instead of official recommendations.

And Ta Da – animal urine is normally yellow!

Ever seen a dog pee on snow?! Don’t eat the yellow snow (as Frank Zappa used to sing).

It was Matt Stone, author of ‘Eat for Heat’ who made me think about the color of urine.

He indicates that urine color should be yellow (about a 4 on the urine colour chart) and a normal specific gravity range is 1.012 to 1.030.

In the recent study on hydration that I mentioned before, properly hydrated participants had a specific gravity around 1.017, which matched a yellow urine color.

Overly hydrated participants had a clearer urine color and dehydrated individuals had a darker urine color.

So to make a long story short: straw-yellow (number 4 on the urine color chart) is probably the color to aim for.

If your urine is clear you might want to cut back on the fluid and if it’s darker you might want to drink a bit more…



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Sources

1. Perrier, Erica et al Urine colour change as an indicator of change in daily water intake: a quantitative analysis Eur J Nutr. 2016 [55: 1943–1949] available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4949298/#CR24
2. Malisova, Olga et al Water Intake and Hydration Indices in Healthy European Adults: The European Hydration Research Study (EHRS) Nutrients 2016 [8(4), 204] available at: http://www.mdpi.com/2072-6643/8/4/204/htm

Kaneko, Jiro Clinical Biochemistry of Domestic Animals (San Diego: Academic Press, 1997), p. 461

Stone, Matt Eat for Heat (Archangel Ink, 2013), p. 21