Effects of lead on human health

Q: Is lead toxic?
A: Yes. Along with some other common metals such as copper, aluminium and silver, lead is toxic.
Other metals we are exposed to such as cadmium, deposited in the environment by agricultural and
mining processes, have similar toxicity to lead.

Q: If these everyday metals are toxic, why are we using them?
A: All these metals can cause toxicity. Human health toxicologists review how each is absorbed by the
body and what level of exposure results in a public health concern.

Q: I thought our bodies needed some of these metals?
A: Yes. Copper is an essential element required at low levels for proper functioning of the body, but it is
toxic in high doses.

Q: Is there a requirement for lead in the human body?
A: No.

Q: What happens to the lead that we ingest?
A: The amount of ingested lead that we absorb depends on various other dietary factors, for example
calcium and protein intake. In a well-nourished adult, around 20% of dietary lead is absorbed and the
rest excreted.

Q: Where does the absorbed lead go?
A: Lead in the body is exchanged between three areas: the blood, the soft tissue, and the bones and
teeth.

Q: How much is found where?
A: More than 95% of lead in the body is in bones and teeth, and less than 5% is in blood and soft
tissues.

Q: How long does lead stay in the body?
A: Lead levels in the blood and soft tissues vary quite rapidly, rising and falling in line with current
exposure over the course of a month or so. Longer term lead accumulation occurs in the bones and
teeth, which can store lead for decades and can therefore be an indicator of lifetime exposure.

Q: Does lead stored in the bones stay there for life?
A: Lead in the bones and teeth usually exchanges very slowly with the blood, but can be released very
gradually over a long time. This exchange may happen more rapidly during certain illnesses or events
such as pregnancy, breastfeeding, kidney disease or broken bones.

Q: Okay, but is there an agreed safe level of lead?
A: No. Just like alcohol, there is no agreed safe level of lead.

Q: How can lead affect human health?
A: Increased levels of lead in the blood are associated with effects such as reduced IQ and hearing,
increased blood pressure, and reduced kidney function. Most people’s blood lead concentration is
below the levels at which these effects have been demonstrated.

Q: Is lead the main factor in these health issues?
A: No. They are heavily affected by other dietary and lifestyle factors. For example, eating a high salt diet
raises blood pressure and is likely to have more impact than lead exposure.

Q: Was lead removed from paint and petrol on human health grounds?
A: Yes. Increased knowledge about lead toxicity prompted the removal of lead from paint and petrol.

Q: Has this reduced our lead exposure?
A: Yes. Blood lead levels are ten times lower than they were 30 years ago. The main source of lead
exposure now is from food.

Q: Which foods do we get the most lead from?
A: In the average diet, we ingest lead through bread, tap water, beer, tea and potatoes. Although these
foods contain very low levels of lead from background sources, they are consumed in relatively large
quantities.

Q: Who advises the government on food safety?
A: Human health toxicologists at the Food Standards Agency (FSA) and the European Food Safety
Authority (EFSA). They both reported on lead in 2012.

Q: Does the EFSA set a lead risk level?
A: Yes. It has set thresholds at which the risk of raised blood pressure or reduced IQ is increased by 1%,
or the risk of kidney problems is increased by 10%. Lead exposure for most people remains well under
these levels.

Q: So where does game shot with lead ammunition fit in?
A: Meat shot with lead ammunition forms a very small part of our diet. It can contain more lead than
other meats, but levels are very variable.

Q: Can I reduce my exposure by removing lead from the meat?
A: Careful butchering may reduce lead exposure from game. Removing lead shot and some tissue from
around the wound channel can help reduce but does not eliminate lead exposure.

Q: What does the FSA think about eating game?
A: FSA advice is that “frequent consumers of lead-shot game should eat less of this type of meat”.

Cooked pheasant

Q: Has the FSA given advice on the number of portions of game that should be eaten?
A: No.

Q: Why do they not specify how much game is okay?
A: Levels of lead in game are very variable. For example, farmed game is not shot, so will contain very
low background levels of lead. Amongst lead-shot game, the amount of lead detected varies widely. This
makes it difficult to set a guideline amount.

Q: What does the FSA say?
A: Because of this variability, the FSA states that “broadly, lead exposure is likely to increase as [leadshot]
game consumption increases” but that “people consuming the largest quantity of game may not
have the highest exposure to lead”.

Q: So how do I know if I am a frequent consumer?
A: We contacted the FSA to clarify this. It suggests that, as a rough guide, individuals who consume
“more than a few items a month” should reduce consumption.

Q: Is this the same for everyone?
A: This advice is especially important for vulnerable groups such as toddlers and children, pregnant
women, and women trying for a baby, as exposure to lead can harm the developing brain and nervous
system.

Q: How many people eat above this level?
A: No one really knows. The UK cost of living survey from 2008 showed that only 0.7% of households
report any expenditure on game. This does not include those to whom game meat comes at no cost,
for example gamekeepers or those who shoot game and then eat it.

Q: Why are some people saying tens of thousands are eating above this level?
A: A survey of BASC members suggested that 13% of those polled eat game once a week or more all
year round. A further 11% of households eat game this frequently only during the shooting season.
These figures were combined and extrapolated to suggest that tens of thousands were exposed at a
high level.

Q: Did the FSA say that game birds should only be eaten twice a year?
A: No. It said that eating lead-shot gamebirds twice a year (or once a month for venison) would have a
minimal effect on our overall exposure to lead.

Q: Okay, but game is lean and high in iron, so it may have health benefits too?
A: Yes. Game can contribute to a varied diet and is considered by many to be a more natural foodstuff
than possible alternatives that may be intensively farmed. The higher lead content must be balanced
against other factors when consumers make choices about their diet.

Q: Has this food paradox arisen before?
A: Yes. Tuna and other oily fish have a wide range of health benefits. But when high levels of mercury
were found in them a sensible approach was taken: human health toxicologists advised certain at-risk
groups to limit their consumption. Even though mercury can be toxic at low levels, they did not advise
we stopped eating fish with high levels of mercury.

Q: Are these the only food components that can be toxic at high levels?
A: No. The FSA advice regarding caffeine is similar to that for lead, with different health risks. It states
that there is a possible link between high caffeine intake and spontaneous miscarriage. Although current
evidence does not allow identification of a safe threshold level, caffeine should be limited but does not
need to be cut out completely. There are also many other compounds, such as alcohol, that can have
negative impacts on health.

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