Download Natural Trans Fats: What We`ve Learned

November 2014
Natural Trans Fats: What We’ve Learned
Adapted from naturaltransfats.ca with permission
Introduction
One of the key areas of discussion
in recent years within nutrition
and health communities is the role
of trans fats in human health.
Key Messages
•
Natural trans fats are different
from industrial trans fats.
•
Natural trans fats are not
harmful when consumed at
normal dietary levels.
•
Pre-clinical studies indicate
natural trans fats may be
health enhancing.
•
Currently, nutrition labels
on food products do not
distinguish between industrial
and natural trans fats.
Much of the public understanding
of trans fats is based on industrial
trans fats. However, advances
in science have contributed to a
steadily growing body of evidence
to suggest that there is a broader
picture to consider – there is also
a separate family of trans fats that
are produced naturally.
Not all trans fats are created
equal
Industrial trans fats are produced
through the chemical process of
hydrogenation during certain food
manufacturing processes or food
preparation approaches.
Natural trans fats (NTF’s) are
produced by ruminant animals
and found naturally in milk and
meat from these animals.
Industrial trans fats. To recap
the fundamentals, in the case of
food product manufacturing,
industrial trans fats are created
when hydrogen bonds are added
to unsaturated fats, converting
unsaturated fatty acids into trans
fatty acids. This conversion is
known as “hydrogenation” and
the resulting trans fats are also
referred to as “hydrogenated fats”
or “partially hydrogenated fats.”
Hydrogenation in food
manufacturing is typically aimed
at increasing the stability and
shelf-life of food products. This
process converts liquid fats,
such as those in vegetable oils,
into more stable, solid fats that
do not spoil as quickly. For the
same stabilizing and preservative
benefits, fats and oils containing
trans fats are also sometimes
favoured as blending agents.
2
for Health Educators
Another way industrial trans fats get into food
is when oils or other fat sources containing these
artificial trans fatty acids are used in cooking. While
this practice has reduced dramatically in recent
years, the use of oils containing trans fats has been
particularly common in commercial deep frying,
since the presence of trans fatty acids allows the oils
to be used for a longer period of time.
Natural trans fats. NTF’s are also produced through
the process of hydrogenation. However, this process
occurs naturally within ruminant animals and the
resulting trans fats are substantially different.1-4
Most of the research on NTF’s has focused on the
types produced by bovine animals, such as dairy
and beef cattle. In the unique ruminant digestive
system, the rumen fore-stomach of these animals
contains thousands of micro-organisms that break
down feedstuff. The current understanding is
that NTF’s are created in the rumen when these
microorganisms break down plant material and
a portion of the resulting components bond with
hydrogen to form a trans fatty acid.5 There is also
evidence that enzymes within the animal may also
support conversion of unsaturated fatty acid into
natural trans fatty acid.5
A portion of the trans fatty acids produced within
ruminant animals is found naturally in the meat
and milk from these animals. For example,
NTF’s are found in all dairy and beef products.
However, while all trans fats share the process
of hydrogenation in common, research has
confirmed that, beyond this commonality, NTF’s
are substantially different from industrial trans fatty
acids in terms of their specific nature, mechanisms
and health implications.5
Journal review bolsters case for natural trans
fats
The body of evidence continues to grow that NTF’s
are not harmful to human health at normal dietary
levels. This is according to an extensive review
published in 2013 in the British Journal of Nutrition,
which discusses the current issues surrounding
trans fat policy and related implications for health,
industry and food labels.6 The review is based on the
most up-to-date scientific evidence spanning several
decades of research and features a wealth of critical
analysis and discussion. Among the highlights:
Major population-based studies show no risk for
cardiovascular disease. A quantitative analysis of
10 large-scale cohort studies7 compares the health
implications of natural versus industrial trans
fats consumed from the diet in populations in the
United States and Europe. It concludes clearly
that in contrast to dietary intake of industrially
produced trans fat, consuming NTF’s from foods
currently available on the market does not affect
the risk of cardiovascular disease (CVD) in healthy
individuals.7
Clinical trials further support findings for
cardiovascular disease risk. Another quantitative
analysis8 – this time of randomized clinical
trials – continues the positive news for NTF’s.
It covers three decades of studies and examines
the differences in CVD risk factors resulting
from dietary consumption of industrial trans fat,
natural conjugated linoleic acid (CLA) trans fat
and other forms of NTF’s. In all, data from 58 trials
involving healthy subjects was considered – 11
focused on the effects of natural ruminant trans fats
and the remainder focused on the effects of CLA
supplements or industrial trans fats. Results indicate
that consumption of NTF’s from dairy products, at
levels achievable in the regular human diet, does
not have any effect on LDL or HDL cholesterol in
healthy individuals.8
Pre-clinical studies indicate health enhancing
potential. Cumulating evidence from animal
studies adds support to these findings while also
highlighting the potential for NTF’s to actually
enhance health.9-14 A leading example is the science
for Health Educators
related to trans-11 vaccenic acid (VA) – the major
NTF generally accounting for 70 per cent of total
NTF’s in the diet.11 Several animal studies10-14
have shown that VA can reduce major CVD risk
factors including blood levels of LDL cholesterol,
triacylglycerol and total cholesterol. Dairy fat
enriched with VA and cis-9, trans-11 CLA has also
shown neutral to beneficial effect on CVD risk.10,15
3
from ruminant animals do not contain any of the
industrial trans fats that are detrimental to health.
In North America and certain other jurisdictions,
a portion of NTF’s content is included in nutrition
labels and not differentiated from industrial trans
fats. Leading researchers would like to see all
NTF’s clearly distinguished from industrial trans
fats in nutrition information, to make it easier for
consumers to make decisions.
Journal articles on NTF’s
To learn more about the latest science,
click here for a listing of key publications in
scientific journals.
Fresh Thinking on Labels
The science points to a need for fresh thinking
on how information on trans fats is presented on
nutrition labels. The science community is working
with the regulatory community to evaluate needs
and potential changes.
“In Canada, the trans fat content is required to be
clearly labeled on food packages, whether it is from
industrially-produced, partially hydrogenated
vegetable oils, or from natural sources such as
dairy fat and ruminant meats,” says Dr. Flora
Wang, co-author of the 2013 review in the British
Journal of Nutrition6 and a leading natural trans
fats researcher. “However, the emerging science
consistently supports a neutral health effect of
NTF’s at levels achievable through a normal diet.
The findings of the review are further evidence that
there needs to be a clear distinction between natural
and artificial (industrial) trans fats in all forms of
public health information, including food labels.”
What’s the bottom line?
The bottom line for consumers? When consumed
as part of a balanced diet, there is no nutrition or
health concern related to NTF’s. Meat and milk
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