The issue of lead in wine became front-page news in 1991 in most American newspapers, despite the fact that most wine contains lower concentrations than scores of other common foods including homemade spaghetti sauce, oranges, spinach or whole wheat bread.
The controversy started when a San Diego law firm forced the U.S. Bureau of Alcohol, Tobacco and Firearms (BATF), which regulates all alcoholic beverages, to release preliminary test data on lead concentrations in wine.
The BATF did so reluctantly, asserting that their tests had not been conducted in a scientifically valid manner and that the results were inaccurate and probably unreliable.
But unreliable as the data were, the public firestorm that followed resulted in press conferences by the Food and Drug Administration (FDA) and the eventual establishment of an interim standard for lead in wine of 500 parts per billion (ppb). By the time you read this, a permanent standard of 150 ppb will probably have been established.
What effect will all this have? Little to none, at least for American wines which, in the BATF tests, showed an average of 41 ppb (with California wines about half of that). Imported wines had higher lead levels, averaging about 94 ppb.
The levels of lead were higher for wine poured from bottles with a lead-foil capsule sealing the neck. Those capsules, however are on their way out and will not be seen on most wine bottled after Dec. 31, 1992.
Older wines which still have lead capsules are safe, but you should wipe down the bottle mouth with a paper or cloth rag before pouring the wine.
Most medical and scientific experts say the publicity over lead in wine is comparable to the scare over Alar on apples which was later shown to have been a tempest in a teapot.
The FDA's activities on wine and lead are "Mickey Mouse," according to Dr. Curtis Klaassen, professor of pharmacology and toxicology at the University of Kansas Medical School. Dr. Klaassen is also the author of the section dealing with lead and heavy metals in the respected medical reference book, The Pharmacological Basis of Therapeutics, used and consulted by most American physicians (published by MacMillan Publishing, Goodman and Gilman, editors).
"Environmental lead is an issue for children, not adults," said Dr. Klaassen who added that lead levels in wine were "irrelevant from a health standpoint."
Dr. Klaassen said the FDA emphasis should be on protecting children, who are far more susceptible to lead than adults. He also pointed out that lead deposited in the bones of a woman before she becomes pregnant could be dissolved and transferred to the fetus during pregnancy, but only if she eats a diet deficient in calcium. "With the proper amount of calcium, the lead stays in place."
"It's [FDA lead/wine actions] a high-profile issue that gets them headlines and makes some points with the anti-alcohol groups," said a professor of medicine at Yale University Medical School who wished to remain anonymous to avoid jeopardizing government research grants. "In my opinion they're wasting a lot of time, money and effort that could be better spent on a real problem -- protecting our kids."
Other medical experts have previously expressed their doubts about the relevance of lead in wine.
"If you drink enough wine for lead to be a problem, you've got a hell of an alcohol abuse problem," said Dr. John Osterloh, Associate Professor at the University of California, San Francisco Medical School.
The FDA's standard for lead in wine -- indeed all their standards governing low levels of lead -- are part guesswork, part science, and partly based on old, conflicting or incorrect data. The standards may or may not have a medically defensible relationship to the health effects of lead in concentrations found in water, wine or other foods.
But these standards are probably the best the government can come up with, given the faulty state of information and scientific research, said the more than 40 state and federal government officials and medical school experts we interviewed.
As a microcosm of government standards-setting, an investigation of the interim lead/wine standard casts serious doubts on the reliability of the data used to establish safety and tolerance levels and raises serious questions about whether the public is adequately served.
"There is no definite answer on how much lead can be safely consumed," said Dr. Dan Paschal at the Atlanta-based Centers For Disease Control (CDC). "The research is not conclusive. We don't know what to measure."
"What's safe?" asked Dr. Osterloh. "The bottom line is that there are no definitive studies and possibly no way to do studies on the effects of lead as low as they are in wine. What's safe? I don't think anybody knows."
"No one really knows what level is healthy," said Rich Nickle of the Agency for Toxic Substances and Disease Registry (ATSDR), a part of the U.S. Public Health Service (PUS).
The FDA had no comment on the soundness of their standard levels or on the validity of the data on which the standards are based.
Numerous telephone calls to the FDA to discuss this situation were not returned.
In addition, our interviews found that different federal government agencies do not agree on the basic data on which the standards-setting process is based. Specifically, different government agencies cited different numbers for:
-- the average amount of lead ingested by the U.S. population in general,
-- the average level of lead in the bloodstream and
-- the blood concentration levels at which health effects from lead start to evidence themselves.
The only generally agreed-upon number defined the relationship between the amount of lead ingested and the corresponding increase in adult blood lead levels. According to the "Uptake Biokinetic Model" developed by the EPA, if an average 150 pound adult consumes one microgram (millionth of a gram) of lead, the blood lead level will increase by 0.32 micrograms-per-liter.
According to the EPA's Jeff Cohen who helped develop the information, the Uptake Biokinetic Model takes absorption of lead and excretion into account.
Research and medical professions generally measure blood lead levels in micrograms-per-deciliter, one-tenth of a liter. But since milligrams-per-liter is equivalent to parts-per-billion (ppb), and since ppb is the most common unit of concentration used for measurements in food by the FDA, water by the EPA and lead measurements by the BATF, this chapter will use micrograms-per-liter for blood lead levels for consistency and to help avoid confusion.
The significance of the EPA's Uptake Biokinetic Model is hard to determine when agencies can't agree on what is a safe level in the blood, how much lead people consume or even what is the average blood level.
The U.S. Center for Health Statistics, a part of the PHS, said they "had no idea of what the levels might be" and didn't know where to look.
ATSDR's Nickle, however, said that numbers for their 1988 "Toxicological Profile of Lead" indicated that blood lead levels might be as high as 170 to 200 micrograms-per-liter, but that other research indicated it might be as low as 60 to 80 micrograms-per-liter.
The ATSDR research indicated that people in remote societies, such as one studied in the Himalayas, had blood lead levels as low as 34 micrograms-per-liter. In their "1988 Report to Congress" that same study indicated that, in general, people in industrialized nations had blood lead levels from 100 to 170 micrograms-per-liter.
Estimates of the average daily intake of lead also vary wildly. According to Ellis Gunderson of the FDA's Contaminate Chemistry Division, the average American consumes about 7 micrograms of lead daily with the figure closer to 6 for women and 8 for men. But that number is not universally accepted.
`I find that hard to believe," said UCSF's Dr. Osterloh, who was the most vocal of more than a dozen skeptics. Many of the other skeptics were officials in federal and state government agencies who seemed reluctant to publicly criticize the FDA. "The average person would get more than that by drinking a quart of water," said Dr. Osterloh. "I'd think the figure was closer to 50."
Other government statistics seem to back up Dr. Osterloh. According to the ATSDR, an EPA study published in 1988 indicated that the average adult male consumed 50.7 micrograms of lead per day and the average female, 37.5, the difference accounted for by the amount of food eaten.
While overall lead intake has dropped in the United States due to the phasing out of leaded gasoline and the declining use of lead-soldered food cans, Dr. Osterloh's suspicions seem justified when examined in light of other government figures.
For example, the current EPA standard for drinking water is 50 ppb. The EPA has also established a new "action level" of 15 ppb to go into effect in 1992.
If a person drank a liter of water per day (a liter is 1.06 quarts) containing 7.5 ppb of lead (half of the EPA action level) then they would consume 7.5 micrograms of lead in the water alone. Since EPA standards are based on the assumption that a person drinks two quarts per day, this scenario would have that person consuming 15 micrograms per day just from water alone, a figure that is twice the FDA's estimates.
In addition, the 7.5 ppb assumption for lead concentrations in water may be toward the low end of reality. According to the ATSDR's 1990 "Toxicological Profile For Lead" prepared in collaboration with the EPA, the average U.S. public water system contains 5 ppb at the source with tap water concentration in homes and schools averaging from 10 to 30 ppb.
Finally, using the FDA's numbers for some common foods quickly raises the average person's intake. Spinach, for example, contains 39 ppb of lead; a person consuming four ounces would add 4.2 micrograms of lead. A two-ounce white bread roll, measured by the FDA at 28 ppb, would add another 3 micrograms. Using these figures, it is easy to see why Dr. Osterloh and others doubt the FDA numbers for total daily intake.
If the EPA's Uptake Biokinetic Model is valid, then it should be possible to work backwards to determine what level of lead intake is necessary to raise blood lead to a given level. If we take a conservative blood lead level, 60 micrograms-per-liter, and divide it by 0.32 (from the Uptake Biokinetic Model's formula), then a person would have to consume 187.5 micrograms-per-day to maintain this blood lead level, which many estimates indicate may be too low for the United States.
Clearly either the FDA consumption data is incorrect, the EPA model is not valid or the ATSDR's blood level data is incorrect.
"It doesn't compute, does it?" commented a source within the FDA who requested that his name not be used. "Now you know why it took us so long to come up with a number (for the lead/wine standard). It's very confusing and we don't have all the facts we need to make the decision," said the source, who was part of the team which developed the interim lead standard for wine.
While all health experts agreed that lead plays no useful role in the human body and that the less lead consumed the better, opinions vary widely about what is safe, what is tolerable and what levels should be set by regulatory bodies.
Acute lead poisoning is fairly easy to diagnose and regulate. According to the ATSDR's "Toxicological Profile For Lead," blood lead levels of more than 400 micrograms-per-liter cause anemia, neurological disturbances, kidney and reproductive damage.
This 400 micrograms-per-liter level is the maximum acceptable occupational level by the federal Occupational Safety and Health Administration (OSHA).
"You need to realize that this level is not necessarily a "safe level," said Dr. Michael Montopoli of the National Institute of Occupational Safety and Health. "Occupational standards must balance medical considerations with the economic impact on industry and thc feasibility of current technology to deal with it. However, there is some debate as to whether the current standard should be lowered."
The ATSDR's "Toxicological Profile For Lead" shows health effects dropping off rapidly below 250 micrograms-per-liter. However, at this level the study indicates that the lead could still cause high blood pressure.
"The EPA bandies about a number of 10 micrograms-per-deciliter (100 micrograms-per-liter) as a defacto acceptable number," said CDC's Dr. Paschal. "But that's a number of convenience. There may be no threshold (safe level) for lead."
According to Neurotoxicology, a reference book by EPA Senior Scientist J. M. Davis, 100 micrograms-per-liter represents a level of low observed effects, but then goes on to state that there may not exist a level with no observed effects. In other words, lead may not have a safety threshold.
According to the "Toxicological Profile for Lead" the only known medical effect for blood lead concentrations less than 100 micrograms-per-liter may be the inhibition of ALA-D, an enzyme involved in the production of red blood cells. "There may be an actual health effect or there may not be," said ATSDR's Nickle.
Medical reference books indicate that inhibition of ALA-D may be connected to high blood pressure which, in turn, has a well-known connection to cardiovascular disease. However, as you have already read in this book, the overwhelming body of research has proved that moderate drinkers have lower cardiovascular death rates than abstainers and heavy drinkers. Indeed, increased blood pressures are only seen in heavy drinkers.
Dr. Osterloh and several other government scientists said they didn't have a lot of faith in "the curve" at lower blood lead concentrations -- especially below 100 micrograms-per-liter. Part of this, they explained, was the reliance on what's known as linear regressive analysis in which the results at high concentrations are extrapolated backwards to lower concentrations -- perhaps concentrations that are too low to measure directly with current technology.
However, as technology advances, scientists have increasingly found that in some cases mechanisms come into play that can effectively neutralize a chemical at low concentrations which is poisonous at higher levels.
This linear regressive analysis is frequently used with substances like lead or low-level radiation which are thought to have no safety threshold.
In everyday terms, linear regression analysis works like this: research indicates that if 100,000 people fell off a 1,000-foot cliff, they would all die. If they fell off a 500-foot cliff, 50,000 would die. If they fell from a 100-foot cliff, 10,000 would die. If taken to its lowest levels, then 100 people would die if the cliff was only one foot high and 10 people would die if it were only one-tenth of a foot.
The method, scientists point out, works in some cases but not in all cases (such as the cliff example).
The proven fact that moderate consumers of alcohol have a 10 percent or more reduced risk of dying from all causes and that wine drinkers have the same -- or perhaps better -- odds indicates that lead in wine has no effect at all. Moreover, even alcoholics have not been found to suffer from lead-related problems. A European study found that alcoholics who drank mostly wine had higher, but non-toxic, blood lead levels than other alcoholics.
But like all scientific problems, answering this question requires a certain set of assumptions. Obviously, the results are wrong if the assumptions are incorrect. And as we have seen, the government's numbers don't always compute.
But for the sake of this argument, assume that:
-- A bottle of wine contains 21 ppb lead (the California average).
-- 21 ppb is equivalent to 21 micrograms-per-liter, which equals 15.75 micrograms in a 750-mi bottle.
-- A 750-ml bottle contains six drinks of wine.
-- One glass of wine contains 2.65 micrograms of lead.
If the EPA's Uptake Biokinetic Model is correct, a person drinking a glass of this wine every day could expect an increase in the blood lead level of 2.63 X 0.32 or 0.84 micrograms-per-liter. This compares to an average blood lead level which may be between 60 and 170 micrograms-per-liter. The 0.84 increase may be considered not significant in relation to the overall blood lead level.
Time and again, experts said, "There are no definite studies," and "We need better science before we can find solid answers."
Until then, wine -- alone among all foods and beverages which contain equal or greater amounts of lead -- remains singled out for the sort of government attention which most experts say is a waste of time.