Good morning.
Welcome to this session dedicated to hydration and children,
it is a great pleasure to be here today.
Before we start, I would like to start by asking you a question.
How many of you have children in the room?
Could you please raise your hand?
Quite a large amount, thank you.
Now I would like to ask you a second question.
Could you please raise your hand if you have never wondered if your child was drinking enough or was adequately hydrated ?
Well done to these 5 people !
This is exactly why we are here today.
We are here to talk about how much children are drinking, how much they should be drinking,
what it means to be adequately hydrated, which biomarkers to use, and most importantly why it matters.
Before we start, I would like to give a little introduction.
Of course, you may have seen some of this in the academy yesterday.
Just as a reminder, water is the most abundant component of the body.
In a child, it makes 60% of their body mass.
Water serves many essential functions in the body such as thermoregulation, waste elimination, or as a carrier, or solvent for reactions.
In fact, professor Kavouras yesterday talked about water as a macronutrient,
and I was thinking when I studied nutrition and they taught me about macronutrients, I never heard the word Water.
If you look at the definition of a macronutrient, which is a substance required in
relatively large quantities for growth, energy, and health, water definitely qualifies for this definition.
In fact, looking at the dietary reference intake for an 8-year old child weighing 25kg,
that child needs 90 times more water than he needs protein in one day.
So water is not only a macronutrient,
it is the most important macronutrient.
Why look specifically at hydration in children?
First of all, for physiological reasons.
We know that children have higher body water content than adults.
When we are born, we are born with 74% of our body mass as water.
I learned from Professor Denis Brown a few years ago that this is the same as a banana.
Within the first year, this reduces down to 60% quite quickly,
and remains relatively stable throughout childhood.
It will then decrease again, especially in women after puberty.
This is obviously partly due to changes in body composition.
Children also have a higher body surface to body mass ratio,
and this translates into higher insensible water loss.
For all these reasons and many other reasons,
they have higher water needs relative to their body weight than adults.
Beyond these physiological reasons, there are also educational and behavioural
reasons that make water important for children.
First of all, we know that children depend upon adults for the provision of water,
and this is specifically true for younger children.
If you think about it, as adults, we often rely on our own thirst to provide water to children.
But we learnt yesterday during the Academy that thirst is not necessarily a great
marker of hydration because often we do not get thirsty until we are actually a bit dehydrated.
For this reason, adults who are low drinkers may not be providing enough water to
the children or not asking them often enough.
This potentially has consequences because low drinkers as adults may be creating a whole new generation of low drinkers in children.
This has consequences later in life because we know that many eating and
drinking behaviors, which are adopted during childhood sustain into adolescence
and even into adulthood. I took the example of one study here, there are many
others like this one, looking at sugar-sweetened beverage intake. This study by
Fiorito published in 2010 showed that the intake of sugar-sweetened beverage at
age 5 predicted the sugar-sweetened beverage intake at age 13 and not only. It
actually also predicted the intake of other nutrients such as added sugars and lower protein and fiber.
So children who have low water intake will potentially
become low drinkers as adults with potential health consequences that we know;
for example on kidney health.
Now that we know why water is especially important for children, Health Authorities
have developed adequate intake for water. This table presents the adequate
intake for water from the Institute of Medicine, and from the European Food Safety Authority.
What you can see here is that they are divided by age categories, and
from puberty, there are sex-specific as well.
We often don’t really know how much water comes from food. But what we can
estimate is that if we take into account that around 20% comes from food moisture,
knowing that this may depend on the country (and cultural habits), the EFSA
adequate intake for water then translate into fluid intake recommendations of 1,3 L
for 4 to 8 yrs old, 1,5 to 1,7 for 9 to 13 yrs old, and 1,6 to 2,0 litres for 14 to 18 yrs
old. I am going to ask you to keep those in mind because we will be looking at the
actual fluid intake versus those recommendations.
So how do we know whether children drink sufficiently or whether they are adequately hydrated?
First of all, we can look at water inputs or we can look at water outputs.
Let’s start with the water inputs.
Among the water inputs, fluid intake is the most important contributor.
To look at fluid intake, we are lucky to have an important database, which has data for more than 11000 people.
You have heard about this database before, it is called Liq.In7 and the results of some analyses have been published in 2 supplements.
You have been given the latest one during this conference.
From this database, we are able to carry several different analyses and I will be focusing today on the children database.
The database encompasses data for more than 6000 children, aged 4 to 17.
For the purpose of this presentation, I haven’t separated them into categories
but this has been done in the previously published articles.
You can see the number of countries, there are 13 of them,
where we have data for children, and it covers quite a large area in the world.
First of all, let’s look at the total fluid intake (sum of all beverages) of the children.
If you look at the overall sample, the mean total fluid intake across all the countries
is 1,5 L per day. Some of you may think “Oh that’s actually quite a lot compared to
those recommendations”. But if you go a little bit deeper and look at the different
countries, what you can see is that for some countries it is very low, such as
Belgium or France where the mean intake is around 1L per day and for some other
countries the mean intake is actually quite high like Indonesia, where it is higher
than 2L per day. So this mean across all countries does not mean anything
because there is very large variability between countries.
Some of you may think that the variability within one country is interesting and it might be due to the age
difference of the sample but if you actually this analysis by age category, you can
see again the same variability so this isn’t due to the age category, this is due to
the internal variability between individuals (within one category). For example if you
take the example of Brazil, you can see that the 5th percentile is around 500mL/day,
that’s 2 servings, or 2 cups, and the 95th percentile is around 3,5L/day. So
that’s an enormous difference between low drinkers and high drinkers.
Now, how does this total fluid intake compare to those recommendations that we just talked about?
This map shows the percentage of the kids population who are drinking less than
the EFSA recommendations that we just talked about. So in dark green, you have
the countries where more than 2/3 of the children do not meet the EFSA adequate intake for water from fluids.
In light green, you can see (countries for which)
between 1/3 and 2/3 of the children not meeting the EFSA recommendations.
In light gray, there is actually only one, Indonesia, where less than 1/3 of children do
not meet the adequate intake.
Again you can see large disparities between countries, but overall in the while
sample of the database, 60% of children do not meet the adequate intake for
water from fluids.
Now let’s dive a little bit further into the different beverage categories.
We know it’s not just how much you drink that matters but also what you drink.
So we were able to look further at different beverage categories and I am going to start with water.
This figure here shows you the distribution of water intake amongst the children.
You can see that quite a large proportion are drinking less than 500 mL per day.
In fact, 1 in 4 children in this database are drinking less than 1 serving per day of water.
That’s one glass, can you imagine that?
Pushing it a little bit further, we looked at the children who do not drink water at all in one day
and 5% of the children in this sample did not drink water on a daily basis.
That’s just enormous.
If you actually look at the country breakdown on the right-hand side graph,
you can see that in some countries, it’s 0 to 1%, and in some countries,
it’s up to 10, 16, and even 21%, that’s 1 out of 5 children, that do not drink water daily.
So you probably think “ok, some of those countries have quite a high total fluid
intake, maybe they are drinking something else”.
This is what we thought too.
So we started looking at the contribution of water and sugar-sweetened beverages to total fluid intake.
This is what you can see on this graph.
In red, the contribution of sugar-sweetened beverages to total fluid intake,
in blue the contribution of water.
And what you can see on the left here is that for half of the countries,
the contribution of sugar-sweetened beverages to total fluid intake is higher than that of water.
You can see some countries of South America here but also some European countries such as the UK or Poland.
If we go a little bit deeper into the sugar-sweetened beverage analysis,
again you can see on the left-hand side the distribution of sugar-sweetened beverage intake among children.
It shows that 55% of children in this sample are drinking one or more serving per day of sugar-sweetened beverages or fruit juices.
That’s more than half, 1 in 2 children.
If you look on the right-hand side, again you can see some disparities between countries.
But I mean look at this graph, it’s just enormous, pretty much a 1/3 of children in
every single country of the database drink one or more glass of sugar-sweetened beverage per day.
Now this obviously has detrimental health consequences.
This graph shows you a literature review, non-systematic review that we
performed, looking at the effect of sugar-sweetened beverage intake in children on
health. What you can see is that compared to non- or sporadic consumers drinking
less than 1 serving per week, children consuming more than 1 serving of sugar-
sweetened beverage per week have an increased risk of dental caries, which is
actually really costly for the healthcare system. They also have an increased risk of
overweight and obesity and metabolic syndrome. So obviously drinking less water
and more SSB (sugar-sweetened beverages) is detrimental for health and may
have further consequences later in life as well.
This closes our first chapter looking at how much children are drinking and how
much they should be drinking. Let’s go into the second part and look at what
actually comes out. For this, we will take a specific look at urine.
If you have been at the Academy yesterday, you will know about some specific biomarkers.
First of all we can look at urine volume, which is very precise but does not taken into account the osmoles.
In terms of urine concentration, we can look at
3 different biomarkers. The first one, which is mainly used in clinical research, is
urine osmolality. It is very precise but does require the use of specific material
which is expensive and complicated to use, so mainly used in clinical research.
Urine specific gravity is slightly less precise but can be used in field work because it is quite easy to do with a refractometer.
Finally, urine color can be measured
using an 8-color chart which was developed by Professor Armstrong sitting here.
It is a very good awareness tool in individuals. All these 3 different biomarkers have different use.
We mainly use urine osmolality in clinical research while individuals can use urine color to assess their own hydration.
In fact, what we know from a study, carried out by Professor Kavouras in 210 children in free-living conditions who provided 24-h urine samples,
is that not only is urine color well correlated with urine osmolality, but children are also able to self-assess their own urine color within one color shade.
So what happens is that, in clinical research, when we look at health outcomes,
we often use urine osmolality and this is what I am going to be talking about further in this presentation.
But just bear in mind that any cutoff or any values of urine osmolality can then be translated into urine color which can be used by the general population.
So what does it mean to be well hydrated, adequately hydrated, for children? What should we aim for ?
When I started looking at this, I came across specific cut off in the literature.
So I googled, sorry pubmed hydration and children and some cut-offs came up,
especially an 800 mosmol/kg cut-off. So I thought this is it, this is my Holy Grail,
this is the cut-off value that I have been looking for.
As a good scientist, someone told me that I should go back to the original article,
and to make sure that my reference was good.
So I went back to the original article, which was an article published in 1965 by
Professor Katz, looking at the concentration ability of the kidney in 20 healthy
adults who were exercising or not in hot conditions, 30°C, under fluid deprivation.
Ok… Erm, so where did the word “Children” appear in this article?
Nowhere! So, so far we do not have any specific cut-off values which are related to health outcomes specific to children.
However, if you pubmed hydration and children and cognition, there will be 14
results that come up on pubmed. I can tell you that I did it again yesterday.
7 of those are reviews, 1 of them is not actually applicable (to children), so that
leaves us with 5 or 6 studies, preliminary studies, looking at the effect of hydration on cognition.
What these studies have suggested is that water intake and/or
hydration by looking at hydration biomarkers have suggested effect on cognitive function,
and this includes short-term memory, or attention.
However, the results are fairly inconsistent because of differences in the protocols,
because some of those studies have assessed hydration and some of them have not.
They have used completely different amounts of water.
Some of them have used very short-term protocol, whereby they give a glass of water
and straight after they look at cognition.
So we are in desperate need of a specific study looking at the effect of hydration on cognition in children.
Luckily enough, the third presenter will be presenting some results today.
But let’s pause there and think for a minute.
Where do children use their cognition? At school.
So we went back to our fluid intake database, and we are lucky enough that we
don’t just have the amount of what they drink, we also have the location where they
drink. And I was specifically interested in looking at how much they drink at school.
What you can see on the pie chart on the left, is that only 14% of the total fluid
intake of children occurs at school. This is where they spend a significant amount
of their time and this is where they use their cognition mainly. You can see on the
right-hand side that this is fairly consistent across countries apart from China.
So let’s stop here and think for a minute. What if? What if that link between
hydration and cognition was real?
And What if we were not giving the opportunity to children to drink at school?
What if we are not making this water available? What if we are banning bottles during classes?
What if we are preventing them from peeing? What are the consequences on their cognition later?
This is further supported by studies that looked at urine biomarkers in children either before or during school.
There is not many of them. Please if you have data or if you are interested in carrying out such studies, do!
There is not much data out there. But what you can see from those clinical studies,
bearing in mind that they are not representative of the general population, is that in
many clinical studies, the mean urine osmolality is higher than 800 mosmol/kg just before or during school.
I would like to finish this presentation by giving some conclusions and key
messages before we carry on looking at hydration biomarkers, cognition, and school programs.
Maintaining hydration is very important for children.
Yet what we see in our sample is that 60% of children do not meet the adequate intake for water from fluids.
We also have clinical studies which suggest that many children may not be adequately hydrated, and this warrants further research.
We need some research on hydration biomarkers in children. There is not enough.
To move towards adequate fluid intake and hydration in children, it would be relevant to identify barriers to drinking water for children.
Do they have water accessible at school? Are they allowed to have a water break?
Is having a water bottle banned in the school? It is also important to encourage healthy drinking practices by the use of children-friendly tools.
We have evidence that the UCC, the Urine Color Chart for children is very well accepted.
They understand it very well, they are able to use it, they understand the concept and they love it, especially younger children!
Those tools can help to monitor daily hydration and to increase water consumption.
There are also some tips that you can see here on the right, which were developed by the EASO (European Association for the Study of Obesity).
Some of these tips include for example having water, starting your day with a glass of water, having water at breakfast.
How many of you give a glass of water to your children during breakfast?
You probably give a glass of milk, or a glass of orange juice, potentially.
So this would be my first advice, start by just putting a glass of water on the table early morning.
Finally, it is important to encourage the consumption of water regularly, especially at school.
If you have any involvement with any school system or any school policies, make
sure you tell them that water needs to be available through fountains, through
bottles, and children need to be able to go to the toilets.
I would like to thank you for listening, I would like to thank the Hydration & Health
department and especially Clémentine Morin, who carried out all the fluid intake analyses
and Juliane Zemdegs who carried out the literature review on the effect of sugar-sweetened beverage intake on health in children.
Thank you.