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The food matrix: food is more than the sum of its nutrients

Authors:
  • Dutch Dairy Association

Abstract

Nutrition research is increasingly often focused on the health effects of whole food products. In fact, a food product as a whole is more than the sum of its nutrients. In science this is called the food matrix. This report provides the latest scientific insights with respect to the matrices of milk, yoghurt and cheese. This paper about the dairy matrix was published in Dutch in Voeding Magazine 2-2017. This is a translation. It can be referred to as Voeding Magazine (EN) 2017(2)1-4 For more information please contact Dr. Stephan Peters peters@nzo.nl
Fosfor
CALCIUM
Eiwit
VET
VERZADIGD
B12
Vitamine
B2
Vitamine
ZINK
magnesium
Jodium
Nutrition research is increasingly often focused on the health effects of
whole food products. In fact, a food product as a whole is more than
the sum of its nutrients. In science this is called the food matrix.
This report provides the latest scientific insights with respect to
the matrices of milk, yoghurt and cheese.
The food matrix:
Food is more than the
sum of its nutrients
Dairy matrix
REPORTAGE
TEKST DR STEPHAN PETERS (DUTCH DAIRY ASSOCIATION, NZO) IMAGE DANNES WEGMAN
This article was published in Voeding Magazine 2 – 2017
1
Food-epidemiological research
studies the relationships within
population groups between the
food intake and the eect on
non-communicable diseases
or health risk factors, such as
increased LDL cholesterol or high blood
pressure. Researchers determine them-
selves whether they study the relationship
between the health eect and a food product
or a nutrient. In the past, most epide-
miological research used to be focused
on relationships between nutrients (such
as calcium, protein or saturated fat) and
health. In the last few years, the focus is
increasingly shifted towards whole food
products, for instance milk, yoghurt or
cheese, when dairy is concerned. This
change of focus leads to new scientific
insights. For example, for some food
products the expected negative eects of
salt and saturated fat on health cannot be
found. On the contrary. Just like bread,
which has a relatively high salt content,
and some dairy products, these products
appear to have a protective eect against
some non-communicable diseases.
Risk of cardiovascular
diseases
The fact that there is a relationship between
the intake of saturated fat and a rise of LDL
cholesterol levels is generally accepted.
LDL cholesterol is a risk factor for cardio-
vascular diseases. As full-fat dairy and
cheese contain relatively much saturated
fat, the conclusion that full-fat dairy and
cheese increase the risk of cardiovascular
diseases is easily drawn. In the previous
Dietary Guidelines (Dutch Health Council,
2006), this conclusion was converted into a
recommendation to consume less than 10%
of the daily energy intake in the form of
saturated fat. Therefore, in 2006 the advice
in connection with dairy was to choose
for skimmed dairy products in the diet.
This advice was based on the idea that the
health eect of a food product is the result
of the sum of the eects of the nutrients
present in this food product.
Food-based dietary guidelines
During the last decade, more studies were
published that looked into the health eects
of food products as a whole. Here think of
the eects of milk, yoghurt or cheese on
cardiovascular diseases. Contrary to what
was to be expected based on the presence
of saturated fat (and salt in cheese), no
relationship was found between the intake
of (full-fat) dairy and an increased risk of
cardiovascular diseases. On the contrary,
if relationships were found these showed
that these dairy products have a protective
eect. These relationships were explained
in the Background Document Dairy of the
new Dietary Guidelines of the Dutch
Health Council (2015). In this document,
the following conclusions were drawn with
respect to the relationship between dairy
intake and cardiovascular diseases:
A connection between the use of dairy
and the risk of coronary heart diseases
is unlikely.
The use of cheese is associated with a
lower risk of coronary heart diseases
(limited evidence)
It is unlikely that the use of total dairy
has any eect on systolic blood pressure
and LDL cholesterol.
Discrepancies in research
There are various explanations for the
discrepancy between the health eects
of the sum of nutrients and those of dairy
products as a whole. One of these expla-
nations can be found in uncertainties in
epidemiological research. Epidemiological
research often finds non-causal connections.
Therefore, it does not make sense to follow
just one single study when defining the
dietary guidelines based on epidemiological
research. The chance of finding a causal
relationship based on epidemiological
studies grows when more studies give the
same results and these studies have been
corrected for disturbing factors, such as
lifestyle, age and eating habits, as much as
possible. When sucient studies have been
published, these can be put together in a
meta-analysis. In case of a lot of evidence
at meta-analysis level (and when there may
possibly also be a dose-response eect), the
evidence is interpreted as being high and
then there is a considerable chance of a
causal relationship.
Confounders
When too few studies are available to draw
conclusions about associations with a high
evidential value, there is a chance that the
connection is not causal, but that here
so-called confounders are involved. These
are factors that disturb, cause or even turn
around the causal connection. In this way,
people who pursue a sportive lifestyle, eat
healthily and have no overweight may
happen to be the ones who consume a lot of
milk or cheese. The Dutch Health Council is
convinced that hardly any confounders are
involved in the connections between dairy
consumption and a lower risk of colorectal
cancer and type 2 diabetes. Now that other
health eects than expected are found in
the consumption of dairy products, a new
question arises based on the nutrients pre-
sent, being 'Why do dairy products protect
against cardiovascular diseases despite the
fact that they contain saturated fat and, in
the case of cheese, even a substantial
amount of salt?'
The matrix effect
We do not eat nutrients, we eat food
products and usually in combination with
other food products during a meal. A food
product has a physically and nutritionally
complex structure that has influence on
the digestion of the food product and the
absorption of the nutrients. The eects of
the structure of a food product are also
defined as matrix eects. Matrix eects
can also change the bioactive properties
of nutrients.
Cheese consumption is associated with
a lower risk of coronary heart diseases
2
Publication of the dairy matrix
Is it possible to explain the 'surprising'
health eects of dairy described above by
the matrix eects? This was discussed in a
multi-day workshop attended by 18 inter-
national scientists of dierent disciplines
in Denmark late 2016. The objective of the
workshop was to more securely define the
term dairy matrix and to get an overview of
the knowledge gaps. These may then serve
as a source of inspiration for further research
into the dairy matrix. The results of the high
level workshop were recently published in
the American Journal of Clinical Nutrition.1
The publication in this renowned journal
shows that there is a broad support base
among fellow scientists about the findings
concerning the dairy matrix.
Dairy matrix
Dairy products dier from each other with
respect to nutrients and structure. Although
cheese has a high fat content, the further
composition of cheese is more similar to
that of yoghurt and milk than to that of
butter where protein, vitamins and minerals
are concerned, of course with dierent
amounts. The fat in dairy cannot be
con sidered without taking the biological
membrane that encloses the fat drops in
milk, the milk fat globule membrane
(MFGM) into account. Yoghurt and cheese
are both fermented dairy products with
bacteria that possibly produce bioactive
peptides and short-chain fatty acids
(SCFAs). When looking at the structure,
cheese has a solid structure, yoghurt a
gel-like structure and milk a liquid structure.
Due to the dierent production processes,
many other dierences can be mentioned.
Because of the dierences in composition
and structure of dairy products, the partici-
pants of the dairy matrix workshop thought
it to be likely that other health eects from
dairy products can be expected than from
the intake of individual nutrients.
Calcium
A good example of a matrix eect is the
dierence in the health eects of calcium
in the form of a supplement and calcium
present in dairy. In the Background
Document Food Supplements for the
Dietary Guidelines, the Health Council
of the Netherlands has studied the eects
of calcium supplements on health. The
conclusions are given below.
A daily use of 1.2 gram calcium supple-
ments lowers the systolic blood pressure
by about 2 mm Hg, but it increases the
risk of coronary heart diseases by about
30% (high evidential value)
The use of calcium supplements increases
the risk of intestinal cancer (in particular
with elderly people; low evidential value)
An eect of calcium supplements on LDL
cholesterol is unlikely
The use of calcium supplements lowers
the risk of hip fractures, in particular with
postmenopausal women (low evidential
value)
When comparing the eects of calcium
supplements with the eects of dairy, it is
notable that supplements (so only calcium)
increase the risk of cardiovascular diseases
and raise the risk of intestinal cancer with
elderly people. This while dairy intake is
particularly associated with a lower risk of
cardiovascular diseases and intestinal cancer.
Dairy matrix
REPORTAGE
A food product has a physically and
nutritionally complex structure that has
influence on the digestion of the food
product and the absorption of the nutrients
3
Saturated fat
Similar dierences in health eects are also
observed for saturated fat and full-fat dairy,
as described at the beginning of this article.
How can the dairy matrix explain these
dierences? A possible explanation is that
the concentration of blood lipids drops
because of a decrease of the fat absorption
in the small intestine. There are indications
that calcium, phosphorus, milk fat globule
membrane (MFGM) and starter cultures in
fermented dairy products have influence
on the blood lipids response by saturated fat.
During the matrix workshop it was suggested
that the MFGM may play a role in the regu-
lation of the blood cholesterol. This justifies
a plea for more studies in this area.
Structure matrix
Apart from the interaction between
nutrients, the structure of a food product
may have an eect on the absorption of
nutrients, saturation and/or other health
aspects. For instance, the consumption of
yoghurt or drinking yoghurt takes away the
sense of hunger more than the consumption
of milk-based drinks or fruit drinks does.
This was shown in a comparative study in
which the appearances and energetic
values of the products resembled each
other as much as possible.2 More such
matrix eects due to the structure of dairy
have been described in literature, such as
the dierent eects of various protein
sources (dairy, meat, fish, egg and plants)
in connection with the risk of type 2
diabetes.3
Health effects with strong evidence
The following associations with strong evidence for total dairy or dairy products
on health effects were found in the most recent Dutch Dietary Guidelines:
The consumption of 400 grams per day of total dairy is associated with a
lower risk of colorectal cancer by 15%
The consumption of 200 grams per day of milk lowers the risk of colorectal
cancer by 10%
If the yoghurt consumption of < 10 grams per day is raised to > 60 grams per
day, this is associated with a lower the risk of type 2 diabetes by 10%
Conclusions concerning
the dairy matrix
There seems to be sucient evidence
that the dairy matrix shows specific health
eects that cannot be explained by the indi-
vidual nutrients from dairy. For instance,
full-fat dairy consumption has an eect
on maintaining a healthy body weight and
lowers the risk of cardiovascular diseases,
type 2 diabetes and poor bone health,
which eect cannot be traced back to
nutrients. There are indications that the
structure of dairy products causes interac-
tions in the dairy matrix that may lead to
various positive metabolic reactions. The
18 scientists who participated in the work-
shop about the dairy matrix reached the
following final conclusion: The nutritional
value of dairy products is more than the
sum of the nutrients. As there still are many
knowledge gaps, it is desirable to do more
research into the area of the food matrix.
Dietary guide lines must be focused more on
health eects of food products as a whole
instead of just nutrients. A nice example of
this are the most recent Dutch Guidelines
for a Healthy Diet from 2015.
References
1 T. Kongerslev Thorning et al. Whole
dairy matrix or single nutrients in
assessment of health effects:
current evidence and knowledge
gaps. Am J Clin Nutr 2017, doi:
10.3945/ajcn.116.151548
2 Tsuchiya et al. Higher satiety
ratings following yogurt
consumption relative to fruit drink
or dairy fruit drink. J Amer Diet
Assoc 2006;106:550-7
3 Comerford et al. Emerging evidence
for the importance of dietary
protein source on glucoregulatory
markers and type 2 diabetes:
different effects of dairy, meat, fish,
egg and plant protein foods.
Nutrients 2016;8:446
For the English version of the Dutch
Food-based dietary guidelines visit
https://www.gezondheidsraad.nl/
sites/default/files/201524edutch_
dietary_guidelines_2015.pdf
A possible explanation is that the
concentration of blood lipids drops
because of a decrease of the fat
absorption in the small intestine
4
Article
The concept of food matrix has received much attention lately in reference to its effects on food processing, nutrition and health. However, the term matrix is used vaguely by food and nutrition scientists, often as synonymous of the food itself or its microstructure. This review analyses the concept of food matrix and proposes a classification for the major types of matrices found in foods. The food matrix may be viewed as a physical domain that contains and/or interacts with specific constituents of a food (e.g., a nutrient) providing functionalities and behaviors which are different from those exhibited by the components in isolation or a free state. The effect of the food matrix (FM-effect) is discussed in reference to food processing, oral processing and flavor perception, satiation and satiety, and digestion in the gastrointestinal tract. The FM-effect has also implications in nutrition, food allergies and food intolerances, and in the quality and relevance of results of analytical techniques. The role of the food matrix in the design of healthy foods is also discussed.
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