2. Hereditary Fructose Intolerance (HFI)
• What is HFI?
• HFI is a condition people are born with, usually
in families where there is no previous history.
The condition makes it difficult for the body ,
chiefly the liver and kidney to use fructose or
fructose – containing foods. The sugar is taken up
by the body, but in attempting to use sugar ,
toxic substances are produced , which lead to
serious illness
4. • In another words :- HFI is an autosomal recessive
disorder of fructose metabolism due to a deficiency of
fructose-1-phosphate aldolase (EC 2.1.2.13) activity,
which results in an accumulation of fructose-1-
phosphate in the liver, kidney, and small intestine.
• The accumulated fructose-1-phosphate inhibits
glycogen breakdown and glucose synthesis, thereby
causing severe hypoglycaemia following ingestion of
fructose (Fi. 1).
• Prolonged fructose ingestion in infants leads
ultimately to hepatic and/or renal failure and
death.
• Patients develop a strong distaste for sweet
food, and can avoid a recurrence of symptoms
chronic course of the disease by remaining on
a fructose- and sucrose-free diet.
5. How is HFI diagnosed?
• The only definitive way to ascertain if one
is suffering from HFI is to have one of two
tests:
1. An enzymatic assay to determine aldolase
activity.
– The aldolase is obtained from patient liver
tissue in an invasive surgical procedure called
a liver biopsy.
2. A fructose tolerance test. Fructose is
injected intravenously under controlled
conditions where acute glucose, fructose,
and phosphate levels are monitored.
6. • HOWEVER, both tests represent
considerable risk, especially in a newborn.
• A newer, non-invasive DNA test is readily
becoming more available.
• While the DNA test is not diagnostic
because negative results do not guarantee
that one does not have HFI, positive
results, along with clinical symptoms, are
strong indicators of disease.
• A presumptive diagnosis can be made.
7. • An unreliable method is the H2 breath
test. The hydrogen breath test is a safe
and noninvasive procedure that may
diagnose fructose malabsorption.
• Following ingestion of fructose, the
hydrogen concentration of the patient’s
breath is measured at various time
intervals.
• An increase above baseline hydrogen
concentration suggests fructose
malabsorption.
• NOTE: This test has not been shown to
be an effective means of diagnosing
fructose intolerance.
8. HFI Treatment
• The normal treatment, if you suffer from HFI, is a strict
fructose free diet.
• This involves exclusion of anything containing fructose,
sucrose, or sorbitol.
• Implementation and adherence to this diet is often difficult,
but not impossible.
• People on this diet live normal and healthy lives, although
the danger of inadvertent fructose ingestion remain.
• Furthermore, it is unclear what long-term effects there
might be on liver function from prolonged neonatal
encounter with fructose. In extreme cases of life-
threatening liver damage, liver transplants have been
performed.
9. • These consequences are not likely if, instead
of HFI, there is a fructose malabsorption
problem.
• Treatment, however, of both is similar.
10. Foods to Avoid
• Eliminating more than just fruit and honey is necessary when
following a low fructose diet because it is present in many
processed foods.
• Read nutrition labels and ingredients lists carefully to determine
what foods are safe and which ones you want to avoid.
• The words fructose, sucrose, sugar, high fructose corn syrup,
honey, sorbitol or sweetened milk indicate the presence of
fructose.
• Clinic, and may cause symptoms in your digestive tract when
eaten.
• If you are unsure about an ingredient, contact the manufacturer
and speak to a representative who can give you more
information about it. Keeping a food diary will help you keep
track of which foods cause a reaction so you can eliminate them.
11. • Fruit
• Although you can safely consume fruit on a low
fructose diet, it is important to know which ones
are high in fructose.
• High fructose fruits include watermelon,
pineapple, oranges, apples, pears, peaches and
mangoes.
• However, some people can tolerate eating some
of these fruits in small amounts and in
combination with other foods.
• Juices from concentrate should be limited
because they contain much more fructose in a
serving than fresh fruits do
12. • Sweeteners
• Sweet foods are likely to contain some form of fructose.
• High fructose corn syrup is one that you should limit or
avoid if you are maintaining a low fructose diet.
• Soda, candy, packaged desserts, yogurt, jam, condiments
and some sports drinks contain this sweetener.
• However, many manufacturers are creating products that
don't use high fructose corn syrup, but be careful because
they are likely to have some other sweetener in them.
• Any food sweetened with sorbitol, fruit juice or honey
should also be limited.
• Aspartame is fructose-free, but health experts debate its
safety so consume it in moderation.
13. What to Eat
• There are plenty of foods you can eat on a low fructose
diet so that you are covering your nutrient needs and
staying healthy.
• The University of Virgina Health System recommends
meat, dairy, eggs, beans and vegetables.
• Combining these foods will create balanced meals that
offer nutrition and protection from health problems.
• The Mayo Clinic advises contacting a dietitian for
advice that is specific to your concerns and for a
comprehensive list of foods you can and cannot eat on
a low fructose diet.
14. • Meats
• Fresh meats contain no fructose. They are also high in
protein and iron, and low in carbs. Red meat, pork and
sausage are all high in fat as well. Chicken and turkey
breasts are lean and contain no fructose.
• Fish
• Catfish, flounder, tilapia, salmon, trout, herring, mackerel
and tuna are all types of fish that are low in fructose. They
are also high in protein and low in carbs. Shellfish, such as
crabs, lobster, shrimp, mussels and oysters are all low in
fructose as well.
• Beans
• Beans in their natural state are free of fructose. They are
also high in fiber, protein and complex carbohydrates.
Broad beans, pinto beans, lima beans, lentils and black
beans are examples. Once any of these beans become
canned and any type of sugar is added, they are no longer
low in fructose.
15. • Whole Grains
• Whole grains have a high fiber content and low
fructose content. They are also high in complex
carbs and have moderate amounts of protein. Oat
bran, oatmeal, millet, Kamut, quinoa, barley and
buckwheat are examples.
• Eggs
• Eggs contain no fructose, are low in carbs and are
high in protein and fat. This includes the yolks and
whites, and egg substitutes as well.
• Seeds and Nuts
• Seeds and nuts are low in fructose, high in protein,
healthy fats and fiber, and low in carbs. However,
any type of seeds or nuts that are honey roasted or
covered with sugar are high in fructose
16. • Vegetables
• The majority of vegetables are low in fructose.
Iceberg lettuce, green peppers, broccoli,
Brussels sprouts, zucchini, radishes, cabbage,
celery and mushrooms are examples.
• Dairy
• Dairy products, such as cheese, milk and
buttermilk are low in fructose. These items are
also high in calcium, protein and fat. Plain
yogurt is low in fructose, but varieties that are
flavored with fruit or high fructose corn syrup
are not.
