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Zellweger syndrome

Zellweger syndrome is a rare, congenital disorder (present at birth), characterized by the reduction or absence of peroxisomes (cell structures that rid the body of toxic substances) in the cells of the liver, kidneys, and brain. It is characterized by an individual's inability to beta-oxidize very-long chain fatty acids in the peroxisomes of the cell, due to a genetic disorder in the PEX2 gene. more...

Zadik Barak Levin syndrome
ZAP70 deficiency
Zellweger syndrome
Zollinger-Ellison syndrome

Named after Hans Zellweger, a former professor of Pediatrics and Genetics at the University of Iowa who did research into the disease, it is also called cerebrohepatorenal syndrome.

VL chain fatty acids are generally found in the central nervous system (brain and spinal cord) and the peroxisomes of these cells cannot import the necessary degrative proteins for B-oxidation to occur. Zellweger syndrome is one of a group of genetic disorders called peroxisomal diseases that affect brain development and the growth of the myelin sheath, the fatty covering—which acts as an insulator—on nerve fibers in the brain.

Symptoms are often exhibited at around 1 to 2 years of age. If left untreated Zellweger's syndrome can lead to major mental retardation and death. The other most common features of Zellweger syndrome include an enlarged liver, high levels of iron and copper in the blood, and vision disturbances. Some affected infants may show prenatal growth failure. Symptoms at birth may include lack of muscle tone and an inability to move. Other symptoms may include unusual facial characteristics, mental retardation, seizures, and an inability to suck and/or swallow. Jaundice and gastrointestinal bleeding may also occur.

There is no cure for Zellweger syndrome, nor is there a standard course of treatment. Infections should be guarded against to prevent such complications as pneumonia and respiratory distress. Other treatment is symptomatic and supportive. The prognosis for individuals with Zellweger syndrome is poor. Death usually occurs within 6 months after onset, and may be caused by respiratory distress, gastrointestinal bleeding, or liver failure.


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DHA & the Omega-3 Revolution
From Better Nutrition, 8/1/01 by Liz Brown

How the margarine craze brought America to the brink of Nutritional Armageddon--and how omega-3s brought us back

BY NOW YOU'VE HEARD THE ADVICE TO BOOST OMEGA-3 fatty acid intake in order to improve your health. It's no wonder. In tandem with omega-6 fatty acids, omega-3s help balance the body by keeping inflammation in check, and by helping mental function, vision, blood pressure, immunity, metabolism and cell-membrane health, notes Andrew L. Stoll, M.D., in The Omega-3 Connection.

But how do you decide what form of omega-3 fatty acids to seek out in food or supplement form, and in what amounts? Where do all of the acronyms--DHA, EPA, ALA--fit into the equation? And what does the latest research suggest in regard to potential health benefits of these friendly fatty acids?

While the topic of omega-3s can seem complex and confusing, it is possible to make sense of it all--and the effort is likely to pay off, health-wise. So sit back, take a deep breath and read on.

Essential facts about essential fats

There are four major kinds of fats found in foods we eat: cholesterol, saturated fat, monounsaturated fat and polyunsaturated fat. All fats are made up of the same basic building blocks--carbon, oxygen and hydrogen. In saturated fats, the carbons in the chain are completely "saturated," meaning that they are "saturated" with all of the hydrogen atoms they can carry. Although most of us don't think about it, some plants and nuts are fairly high in saturated fat--coconut oil, palm/palm-kernel oil, peanuts and walnuts. Other examples of saturated-fat rich sources include butter, animal fat, shea nut butter and cocoa butter.

Monounsaturated fats, part of the now-famous Mediterranean Diet, include olive and almond oils, pecans, cashews and macadamia nuts. Unsaturated fats with two or more double bonds are known as "polyunsaturated," which includes both omega-3 fats (found mostly in algae, cold-water fish, dark-green vegetables and certain plants) and omega-6 fats (found mostly in nuts and seeds). Examples of foods rich in omega-3-rich polyunsaturated fats are ocean-dwelling microalgae, fish oil, flaxseed oil, hemp oil, pumpkin seed oil. Examples of foods rich in omega-6 polyunsaturated fats are vegetable and seed oils. Some excellent omega-6-rich foods are borage, evening primrose oil, safflower oil, sunflower seeds, hemp seeds, corn and pumpkin seeds.

Fats out of balance

"The good news is that our evolutionary ancestors didn't have a problem with an imbalance of omega-6 fats compared to omega-3 fats--their ratio was close to 1:1," said James Gormley in DHA, A Good Fat (1999). "The bad news is that we do have a problem. The typical U.S. diet has a profile of anywhere from 10:1 to 22:1 omega-6 to omega fats."

Over the past 50 years, the cholesterol/low-fat craze pushed Americans into a diet top-heavy in omega-6 seed oils and trans fatty acids (from traditional stick margarine and fried foods). In other words, most of us get plenty of omega-6s in our diets, but not enough omega-3s.

The omega-3 polyunsaturated fats are headed up by alpha-linolenic acid, or ALA from this, the following fats can be produced: eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and docosapentaenoic acid (DPA). The "mother of all omega-6 fats" is linoleic acid, from which we can produce gamma-linolenic acid (GLA), dihomogamma-linolenic acid (DGLA) and arachidonic acid (AA).

Hearts love omega-3s

Heart disease kills roughly half a million Americans each year, so eating right for heart health should be high on everyone's priority list. Harvard's Walter Willett, Ph.D., M.D., wrote: "It can be conservatively estimated that approximately 30,000 deaths per year in the U.S. are attributable to trans fatty acids from partially hydrogenated vegetable oil" [e.g. traditional stick margarine]. While cholesterol and saturated fat contribute to heart disease, omega-3 fatty acids can actually reduce the risk of heart disease in several ways.

For one, they keep inflammatory processes associated with coronary artery disease and driven by omega-6s in check. If our intake of omega-6s isn't balanced by omega-3s, this can encourage heart attack, atherosclerosis and fatal cardiac arrhythmias, explains Stoll in The Omega 3 Connection. Inflammation caused by excess omega-6 fats plays a major role in promoting the development and buildup of plaques in coronary arteries, which can be damaged by inflammation and eventually lead to narrowing or entire blockage of the coronary artery, resulting in a heart attack. Excess omega-6 fats also increase platelet aggregation (or stickiness), potentially causing blood clots that, when large enough, can block blood flow and result, again, in a heart attack.

The omega-3s, EPA and DHA, conversely, reduce platelet stickiness and clotting, also preventing plaque buildup by raising levels of HDL, or good cholesterol.

DHA/omega-3 research and the heart

1997. Balance of good fats and reduction of trans fats are most important to reducing the risk of coronary heart disease, especially in women. A landmark study came out in the New England Journal of Medicine on November 20, 1997 that looked at 80,082 women who, in 1980, did not have any sign or history of coronary disease, stroke, cancer, hypercholesterolemia or diabetes. In 14 years of follow-up, the authors documented 959 cases of non-fatal myocardial infarction or death from coronary heart disease. Total consumption of fat was "not significantly" related with the risk of coronary disease. The authors calculated that replacing a portion of trans fats (like margarine and other partially hydrogenated oils) with monounsaturated fats (like olive oil) and polunsaturated fats (like DHA) "would decrease [coronary heart disease] risk by 53 percent"!

1998. In addition to supplementation with purified DHA, DHA in eggs may help additional people boost their cardiovascular-health-promoting levels of DHA. S.M. Herber-McNeill and M.E. Van Elswyk, of Texas A&M's Department of Poultry Science, looked at cardiovascular health and a different way of delivering the enriched microalgae-source DHA--through supplementing the feed of egg-laying hens with DHA. The author's study of consumer acceptance of DHA-enriched eggs appeared in the journal, Poultry Science, and is, the authors say, an attempt to address the fact that fish consumption in the U.S. averages less than one serving per week.

1999. Margarine/trans fats and heart disease. In this study (Biological Research [Santiago]), the researchers state that "industrial [partial] hydrogenation of vegetable or marine oils is [....] the main source of trans fatty acids in our diet." The authors contend that "trans isomers [trans fats] are considered more atherogenic [heart-disease causing] than saturated fatty acids."

2000. Postmenopausal women and coronary heart disease. Recent research by Bruce Holub's team at the University of Guelph, Canada, looked at omega-3 marine-oil supplementation in 36 postmenopausal women, some of whom were already receiving hormone replacement therapy (HRT). The results? Supplementation lowered triglycerides by 26 percent; the ratio between triglycerides to HDL, or good, cholesterol was lowered by 28 percent. According to the authors, supplementation could "potentially reduce the risk of coronary heart disease by 27 percent in postmenopausal women."

DHA/omega-3s--the Brain and vision

DHA is a crucial part of the phospholipids of cellular membranes, particularly in the brain (which is composed largely of fat) and retina. It's essential to the growth and development of infant brains and is needed to maintain normal brain function in adults, too. While some organ systems can incorporate ALA from plant sources, the human brain needs DHA and EPA, found primarily in fish oil, according to Stoll Newborn babies seem to be better at transforming MA to the longer-chain omega-3s than are adults, he explains, but the conversions may still be inadequate. Soon vegetarians may be able to buy DHA supplements made from algae, which is where the fish get these omega-3s in their diets.

Sources of DHA include fatty fish (salmon, tuna, mackerel) and mother's milk. (DHA is found in the milk of all lactating women, though amounts can vary based on diet.) For babies who aren't breast-fed, however, DHA- and DHA/AA-supplemented formulas can provide the needed good fats.

Thanks to a letter published by the U.S. Food and Drug Administration (FDA) on May 17, infant formula makers in the U.S. can now sign agreements to include patented DHA and AA blends in all term infant formula. Although the fats are not yet included in formula, look for them in the near future, as soon as formula makers fulfill the FDA's pre-market notification procedures.

This is great news, since healthy, full-term, formula-fed infants have better vision when fed formulas including DHA. Deficiencies of this important omega-3 are associated with fetal alcohol syndrome, adrenoleukodystrophy (ALD), cystic fibrosis, long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency (LCHADD), Zellweger/Pseudo-Zellweger syndromes, Folling's disease/PKU, retinitis pigmentosa, unipolar depression, aggressive hostility, attention deficit hyperactivity disorder (ADHD) and other problems. As we age, DHA helps keep us sharp. Decreases of this omega-3 in the brain often accompany cognitive decline in aging and the onset of Alzheimer's disease.

Milestones in DHA-supportive Research

The Pediatrics study. There were several groundbreaking studies which came out in 1998, the first of which appeared in the journal, Pediatrics. The authors of this study, L. John Horwood, Msc, B.A., and David M. Fergusson, Ph.D., reported that in an 18-year study of over 1,000 children, those who were breastfed as infants were "more intelligent" and had attained greater academic achievement than those who had been fed standard infant formula.

The children who had been breastfed were even 38 percent more likely to complete high school than were the formulated kids. The authors described it this way: "The weight of evidence clearly favors the view that exposure to breast-feeding is associated with small, but detectable, increases in childhood cognitive ability and educational achievement, with it being likely these increases reflect the effects of long-chain polyunsaturated fatty acid levels and, particularly, DHA levels on early neurodevelopment." How is this supportive of DHA? Since the DH-enriched formulas out there match breast-milk levels of DHA, the connection is clear.

The Pediatric Research study. In this study, conducted by E.E. Birch, and colleagues, 79 healthy full-term infants received either a standard infant formula (not fortified with DHA or AA) [control group] or the same formula enriched with DHA or DHA and AA for 17 weeks. The visual acuity (vision), growth and fatty-acid profile of these babies were compared--over the first year of life--with those of exclusively breastfed infants. The infants fed DHA and AA developed vision on par with breastfed babies; the visual development was significantly poorer in the standard-formula-fed group. To put it in perspective, infants fed standard formula had a visual deficiency of about "one line on an eye chart." In fact, the beneficial "effects of dietary supply of DHA on [visual] acuity were still" evident at 52 weeks [one year later], even though DHA was only provided for the first 17 weeks. The study concluded that: "early intake of DHA and AA appears necessary for optimal development of the human brain and eye."

The prestigious Nutrition Information Center of New York Hospital-Cornell Medical Center and the Memorial Sloan-Kettering Cancer Center issued a statement about this study, saying: "The Nutrition Information Center applauds this research which lends support to our conviction that optimal brain and eye development requires docosahexaenoic acid (DHA). This study supports the conclusion of many other similar well-controlled studies which have been reported in the literature over the last 20 years."

The Lancet study. In this study, 44 term infants were randomly assigned to receive a standard formula or a DHA (long-chain polyunsaturated fatty acid) enriched formula, which they received from birth to age 4 months. At 10 months of age, cognitive (learning) measurements were used to compare both groups. The results were impressive. The authors found that "an infant's three-step problem solving ability is significantly improved with [DHA and AA-supplemented formula]."

No fishing pole required

Omega-3 fatty acids have additional health benefits, but those listed above should give you enough reason to boost your omega-3 intake. So how can you get more omega-3s? Some of the research on omega-3s has been done with fish and fish oil, which contain EPA and DHA. Eating fish is one way to get more of both, but limit your intake of tuna and other fish (especially pregnant and lactating women) that may be contaminated with mercury or cancer-causing pollutants such as PCBs. Freshwater fish are more likely to be contaminated than ocean species. Healthy alternatives include migratory Atlantic or Pacific salmon, deep-water halibut and Atlantic cod.

If you're choosing supplement s, aim for either 200 mg of purified DHA daily or one-to-two grams (1,000-2,000 mg) daily of total omega-3 fatty acids (EPA plus DHA). People taking blood thinners including warfarin or aspirin, and pregnant and lactating women, should consult their healthcare practitioner before taking omega-3 supplements.

Although controversy continues about the body's ability to convert ALA to DHA and EPA, vegetarians can eat foods high in ALA--such as flaxseed and other land-based plants--and algae-source DHA supplements. Flaxseed oil is relatively inexpensive in liquid form and is highly concentrated in ALA (it's also available in capsules).


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COPYRIGHT 2001 PRIMEDIA Intertec, a PRIMEDIA Company. All Rights Reserved.
COPYRIGHT 2001 Gale Group

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