and Diet Recommendations for people with Chronic Hepatitis C
Nutrition and the Liver:
The liver is the major organ responsible for regulating and responding to your
body's metabolic demands. Your liver must be functioning well to maintain normal
metabolism of carbohydrates, fats, and protein; it is also responsible for processing
and using several vitamins. This section deals with the role and healthy liver
(and a healthy, well-balanced diet) plays in these nutritional processes.
The most common sources of dietary carbohydrate are sugars, such as sucrose
(table sugar), fructose (corn syrup), and lactose (milk sugar), and starches,
such as breads, pasta, grains, cereals, fruits, vegetables, and potatoes. When
you eat carbohydrates, specialized enzymes in the pancreas and gut process them
to yield simple sugars (glucose, galactose, fructose, maltose).
These sugars are absorbed
by intestinal lining cells, enter the portal circulation, and travel to the
liver via the portal vein. During overnight fasting, blood sugar levels dip
to a relatively low level, insulin secretion is suppressed, and blood insulin
levels diminish. After a meal, blood sugar increases (stimulating the release
of insulin from the pancreas), and insulin levels rise. Insulin, which rises
in response to a meal, is the hormone that stimulates the liver to take in more
glucose and to move the glucose into storage -- mainly in the form of glycogen.
The liver can then release glycogen to your muscles for energy during periods
of fasting or exercise. Although the liver can store considerable amounts of
glycogen, it is the first energy source used during periods of prolonged fasting
or caloric deprivation, and it can be depleted rapidly. After glycogen, the
body taps other energy sources -- including protein and fat.
We take in dietary protein from dairy products, produce, and meats. Enzymes
produced by the pancreas and intestine break down the protein into its amino
acids and small peptides. The intestine rapidly absorbs the amino acids with
specific transport systems within its lining cells and then delivers the amino
acids to the liver via the portal vein. When they reach the liver, they are
used for energy or for making (synthesizing) new proteins. The newly synthesized
proteins perform specific body functions.
In general, fats are neutral lipids (triglycerides), acidic lipids (fatty acids),
and sterols (cholesterol, plant sterols). Triglycerides (dairy products, meats,
oils, butter, margarine) are the most common type of dietary fat and represent
a major source of energy. The liver is uniquely suited to regulate and process
Dietary triglyceride is
digested in the intestine by lipase, an enzyme secreted by the pancreas in response
to meals. Bile, secreted by the liver, makes the digested fat soluble and promotes
its absorption. Absorbed fat is then repackaged and transported into blood,
where the liver ultimately removes it from the circulation. Fat that reaches
the liver is processed in three ways: (1) stored as fat droplets in liver cells,
(2) metabolized as a source of energy, and (3) repackaged, secreted back into
blood, and delivered to other cells in the body.
The liver is also intimately
involved with the processing of dietary cholesterol and is the main source of
newly synthesized cholesterol in the body. Liver disease may be associated with
both high or low blood cholesterol levels. In general, as liver disease progresses
in patients with hepatitis C, the blood level of cholesterol drops.
The liver produces and secretes a fluid (bile) that enters the intestine to
aid in digestion and absorption. Bile is clear yellow to golden-brown and contains
water, electrolytes (salts), cholesterol, bile salts (detergents), phospholipids,
and proteins. Bile helps to activate enzymes secreted by the pancreas and is
essential for the digestion and absorption of fat or fat-soluble vitamins.
The liver plays a role in several steps of vitamin metabolism... Vitamins are
either fat-soluble (Vitamins A, D, E, and K) or water-soluble (Vitamin C and
the B-complex vitamins).
Patients with advanced liver
disease may become deficient in water-soluble vitamins, but this is usually
due to inadequate nutrition and poor food intake. Vitamin B12 storage usually
far exceeds the body's requirements; deficiencies rarely occur due to liver
disease or liver failure. When dietary intake drops, however, thiamine and folate
commonly become deficient. Oral supplementation is usually all that you need
to restore thiamine and folate stores to the normal range.
Fat-soluble vitamins require
not only adequate dietary intake but also good digestion and absorption by the
body. That's why normal production of bile is essential. Bile in the gut is
required for the absorption of fat-soluble vitamins into the body because these
vitamins are relatively insoluble in water. Bile acts as a detergent, breaking
down and dissolving these vitamins so they may be properly absorbed.
If bile production is poor,
oral supplementation of vitamins A, D, E, and K may not be sufficient to restore
vitamin levels to normal. The use of a detergent-like solution of liquid vitamin
E (TPGS) improves the absorption of vitamin E in patients with advanced liver
disease. The same solution may also improve the absorption of vitamins A, D,
and K if the latter are taken simultaneously with the liquid vitamin E.
Source: "Living with
Hepatitis C: A Survivor's Guide" by Gregory T. Everson, M.D., and Hedy Weinberg.
1997, Hatherleigh Press.