The other day I was enjoying a glass of milk. It reminded me of when I was a child and I was often told to drink milk for strong bones and teeth. Milk is rich in Calcium, which is great for strengthening bones. But I began to wonder how effective milk is for mild dehydration, and if it can serve as a substitute for water to help you rehydrate?
After doing some research, I found that milk is definitely effective for rehydration. Furthermore, your body retains milk for a longer period of time than water, but that doesn’t mean that you should only drink milk.
In this article, we’ll cover some common questions about milk in relation to hydration, including:
- Does Milk Hydrate Adults and Count As Water Intake?
- Is Milk More Hydrating Than Water For Adults?
- Is Milk Healthier Than Water?
Does Milk Hydrate Adults and Count As Water Intake?
Yes, milk definitely counts as water intake, and helps hydrate adults, regardless of the type of milk you drink.
Milk is a great choice for those suffering from mild dehydration.
According to this article by Milk Facts, milk is generally around 87% water. The remainder of milk is composed mostly of carbohydrates ~4.9%, fat ~3.4%, and protein ~3.3%.
If you’re doing the math, you’re correct; those numbers don’t quite add up to 100! Vitamins, minerals, and other small proteins and enzymes make up the remaining ~1.5% of milk.
Many people assume that 1% milk just means whole milk that has been watered down further, but that is not necessarily the case.
1% milk still contains very similar contents of carbohydrates, protein, and minerals as whole milk (or 3.25%). In fact, the percentage displayed on your milk jug (1%, 2%, etc.) is in relation to the percentage of fat contents.
Regardless of the type of milk you choose to drink, it will typically consist of between 85% to 90% of water.
Much like eating foods rich in water (watermelon, strawberries, lettuce, soup, etc.) will help hydrate you, so will milk. If you struggle to drink a glass of milk by itself, there are a number of other ways to consume it.
For example, you can have it in cereal, add it to smoothies, or in your coffee/tea. You can even add chocolate powder to it and enjoy a glass of chocolate milk!
Is Milk More Hydrating Than Water For Adults?
A recent study in The American Journal of Clinical Nutrition found that milk was more hydrating than water for adults. This is because milk (full-fat and skim) is retained by your body for a longer period of time than water.
A lot of the liquid we drink flows right through our body, and we signal to our kidneys to dispose of extra fluid by urinating more often.
However, beverages with higher nutritional content are retained in our bodies for a longer period of time than water. Such beverages like milk, that have higher contents of sodium and potassium, help to retain liquid in our bodies and make us more hydrated.
Do you ever have a few glasses of water, only to realize you soon need to go to the bathroom? And then go again not much long after?
This because water lacks nutrients and electrolytes and causes your stomach to empty these fluids quite fast. While water is the optimal source of hydration, milk can be retained in your body for a greater amount of time than water, thus keeping you hydrated for longer periods.
Below, I’ll go into more detail about the specifics of the research study.
How Hydrating Is Milk? – The Study
The study’s objective was to investigate the urine output of commonly consumed drinks to establish a hydration index. Commonly consumed drinks included:
- Still Water
- Sparkling Water
- Diet Cola
- Sports Drink
- Oral Rehydration Solution
- Orange Juice
- Hot Coffee
- Hot Tea
- Cold Tea
- Full-Fat Milk
- Skim Milk
72 physically active men, with a mean age of 25 years old were instructed to consume 500 ml of still water over a 15 minute period, one hour before arriving at the lab.
After arriving at the lab, they each consumed one liter of an assigned common drink over a 30 minute period. They were instructed to drink four equal servings every 7.5 minutes.
Next, they were asked to urinate at the end of the 30 minutes, and at the end of each hour for the next four hours. Total urine masses were then recorded and summed up.
A smaller urine mass (less urine) would mean more fluid (from the commonly consumed drink) was retained in an individual’s body.
Furthermore, if an individual retained more fluid in their body, it could indicate that the commonly consumed beverage they drank was more hydrating than other options.
Results showed that over a four hour period, urine mass for water was 1337g, for an oral rehydration solution the mass was 1038g, full-fat milk the mass was 1052g, while skim milk the mass was 1049g.
This shows that urine output over a four hour period was less for a rehydration solution, for full-fat and skim milk, than it was for water and the other nine commonly consumed beverages.
This proves that milk (skim or full fat) is a great source hydration, and can be retained in your body for longer periods of time than water.
Considering water as the baseline, in the table below you can see the difference between urine mass for a hydration solution, skim milk, and full-fat milk.
|Type of Beverage||Oral Rehydration Solution||Skim Milk||Full Fat Milk||Water|
|Total Urine Mass (g)||1038||1049||1052||1337|
|Difference From Water (g)||299||288||285||0|
Is Milk Healthier Than Water?
Water is typically the first beverage I think of when I realize I need to rehydrate. As your body is composed of over 60% water, it is natural to think that water is the best option when you are feeling dehydrated.
In addition, it is the most basic, and readily available drink in the world. However, water by itself is quite plain. It doesn’t provide any nutritional value.
However, milk provides nutritional value in addition to being a great option when you are experiencing mild dehydration.
Amongst the carbohydrates, fat, and protein found in milk, it also has essential vitamins (vitamin A, B12, D, etc.) and minerals (calcium, potassium, sodium, etc.) that are important to living a healthy life.
For example, an 8 oz (237 ml) glass of 2% milk contains a good amount of your suggested daily intake for these vitamins and minerals (see table below).
|Vitamin Or Mineral||Vitamin A||Vitamin B12||Vitamin D||Calcium||Potassium||Sodium|
|% Of Daily Intake||~15%||~47%||~50%||~30%||~8%||~7%|
Values found in the table above are from Nutritional Components in Milk by Milk Facts. Values are a percentage of the daily reference intake.
Therefore the answer is yes. Milk is a healthier option than water when considering the nutritional value and hydration benefits of both beverages.
Now I’m not saying stop drinking water and only drink milk. There is a time and place, and both drinks should be consumed in moderation.
Milk is heavy and quite filling, it is not something you would want to be consuming while you are exercising. Water, on the other hand, is very light, easy to consume, and a great choice while exercising.
The idea for this article came to me the other day when I was enjoying a glass of milk. I began to wonder if milk is effective for someone who is experiencing mild dehydration and if it can be used as a substitute for water to help you rehydrate.
After doing some research, I found that milk is definitely an effective solution for those experiencing mild dehydration. Furthermore, milk is retained for a longer period of time in your body than just water.
This is because milk contains nutritional contents such as sodium and potassium. These minerals stop our bodies disposing (urinating) of milk as fast as we do with water, which flows through our bodies quite fast.
This information was concluded in a recent study published in The American Journal of Clinical Nutrition, which I discuss in further detail throughout the article.
The study found that of 13 common beverages tested, skim milk and full-fat milk were retained in your body for longer periods of time than all test beverages except an oral rehydration solution (such as Liquid I.V.).
The oral rehydration solution placed first, which is no surprise as it is designed specifically to rehydrate you more efficiently and effectively than water or other drinks. We recently wrote an article, Best Hydration Drinks For Runners, which provides more details on the effectiveness of hydration solutions if you are interested.
Finally, I discussed if milk is healthier than water. And while water should definitely not be forgotten about, milk does provide more nutritional value than water. Milk also has many hydration benefits as it contains ~87% water.
Were you aware of all the benefits that milk offered?
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Facts for this article are referenced from credible sources. For further information, please read these referenced articles from the following organizations:
- Milk Facts – Nutritional Components in Milk
- The American Journal of Clinical Nutrition – A randomized trial to assess the potential of different beverages to affect hydration status