In recent years, it has been said that there is a group of foods that threaten our health and that you should stop consuming them. Actually, they have been named “The 5 White Poisons”. Those are pasteurized milk, white rice, salt, sugar, and wheat flour.
With so much and so contradictory information spread by the media, it is difficult to know what to do.
Should you follow the official recommendations to have a “balanced” diet that includes dairy and cereals or have a more radical “avoid the 5 White Poisons” approach?
In order to provide some clarity, we start today with a series of posts where we will analyze each of these five suspects. We will see how much scientific basis for such a tag is out there.
We are starting with the milk, but first we are going to return for a little while to the classroom, more precisely to the Language class.
Let’s understand the words
First, let’s try to understand the meaning of poison.
The first definition found in the Cambridge Dictionary says that poison is any “substance that can make people or animals ill or kill them if they eat or drink it” (source)
I don’t know you, but I have never seen someone falling dead (or getting badly sick) for drinking a cappuccino with two tablespoons of sugar or for eating a rice stew.
Let’s better look for a more accurate definition of poison. For example, the one proposed in the 16th century by the considered Father of Toxicology, Theophrastus Phillippus Aureolus Bombastus von Hohenheim (for his friends, Paracelsus) who said “All things are poison and nothing is without poison. Solely the dose determines that a thing is not a poison” (source)
That is, depending on how much of a substance is ingested, it turns it into poison or not.
With this concept clear, let’s analyze the first of the 5 White suspects.
During our first years of life, human beings consume breast milk, which means that as babies we were perfectly adapted to it. As we grow, the expression of the lactase gene decreases, which is the main enzyme responsible for digesting milk.
For some people, the lactase expression persists (source) and that is why we find people who consume milk without any problems while for others it produces some issues.
An interesting detail. Humans are the only species that consume milk as adults and from another species, isn’t this strange?
Milk is quite nutritious though. It not only provides calcium but also interesting amounts of other minerals such as phosphorus, potassium and selenium as well as different vitamins (source).
It also provides basically equal amounts of the 3 main macronutrients: proteins, fats and carbohydrates.
Many say that pasteurized and ultrapasteurized milk is unhealthy.
Those types of milk were heated to 70 °C (pasteurization) and 140 °C (ultrapasteurization) in order to eliminate potentially dangerous microorganisms.
Critics argue that these processes kill beneficial bacteria and vitamins, destroy proteins, and hence, increase the risk of Cancer, Diabetes, Osteoporosis, and several allergies. They recommend drinking raw milk instead.
Let’s break this down..
Destruction of beneficial bacteria and vitamins
Logically, heating does not discriminate between good and bad bacteria, almost all of them are destroyed.
But we need to consider the concept of risk/benefit.
I prefer to lose some beneficial bacteria (which can be easily incorporated by consuming fermented food) rather than run the risk (minimal, but real) of suffering an infection with Salmonella, E. coli, Listeria, Campylobacter or Mycobacterium bovis, the latter causing tuberculosis (source) (source) (source) (source).
Pregnant women, children, the elderly, and immunosuppressed people are especially sensitive.
Regarding the destruction of vitamins, a meta-analysis (statistical analysis of the results of several studies) of more than 40 studies shows that the loss of vitamins is minimal after pasteurization (source)
However, from a digestibility point of view, heating to ultrapasteurization temperatures improves the assimilation of protein nitrogen by the body (source).
In summary, milk proteins are little affected by heating, and it also does not deteriorate their nutritional quality.
Undoubtedly, the most serious accusation that milk has is as an alleged cancer promoter.
In regards to this, the scientific evidence is not entirely conclusive. There are studies that link it to cancer while others do not.
In those cases the key aspect to consider is the type of study we analyze. Many of them show association, that is, that two things happening together at the same time does not imply that one causes the other (in this case, that the consumption of milk causes cancer).
Let’s see what studies are there for the most common types of cancer
1- Lung Cancer
A review of 32 studies didn’t find association between milk and other dairy foods with cancer (source).
A meta-analysis, in which more than 10,000 cases were assessed, didn’t find any association with lung cancer neither (source).
2- Breast Cancer
A review of 27 studies including 1,600,000 participants concluded that dairy consumption is inversely associated with the risk of developing breast cancer (source).
A meta-analysis of 46 studies evaluated a potential association between different sources of protein (one of them milk) with cancer. In the case of milk, the association was null (source).
3- Colorectal Cancer
A meta-analysis of 15 studies that included more than 5,200 cancer cases found no association between consumption of unfermented milk (milk, butter and cream) and the risk of colorectal cancer (source).
Another similar study went further and concluded that a consumption of milk/dairy reduces the risk of this type of cancer (source).
4- Prostate Cancer
So far milk seemed to be completely innocent, however the situation changes a bit for prostate cancer.
A meta-analysis of 32 studies finds a positive association between consumption of milk as well as other dairy products with this type of cancer (source).
Another study shows that milk can stimulate in vitro growth (in laboratory conditions) of prostate cancer cells (source).
Who are the suspects?
a. The main one is the hormone IGF-I, which is a growth promoter. Milk consumption would stimulate the production of IGF-I (source) (source) (source). And there are studies that associate IGF-I with cancer (source) (source) (source).
But as said above, association does not imply causation and in fact some argue that it may be the other way around, that is, that cancer is actually the one that causes the increase in IGF-I (source).
In any case, if we consider that cancer is basically an uncontrolled multiplication of cells producing an abnormal growth, it sounds logical trying to avoid anything that stimulates growth. In this case, milk.
On the other hand, in the fatty portion of milk, there is a fatty acid called conjugated linoleic acid (CLA) which seems to have protective properties against cancer, especially breast cancer (source) (source) (source).
Grass-fed cows produce the higher concentrations of this fatty acid (source).
Therefore, if you are going to drink milk, the best option is full-cream, pasteurized and from grass-fed cows.
Allergic reactions to milk occur in 2-3% of babies and young children (under 3 years old) (source). However, after 3 years of life and up to 16 years of age, tolerance develops in 85-90% of these children (source).
IgE antibody mediated allergy usually manifests within 30 minutes of ingestion as inflammation, hives (rash and itching), and in severe cases, anaphylaxis.
On the other hand, allergic reactions not mediated by IgE take longer to manifest (from 2 hours to several days) and show symptoms that affect the digestive tract such as vomiting, diarrhea or constipation and inflammation of the intestinal wall (source).
The recommendation in those cases is simply to eliminate the consumption of dairy products and to perform tolerance tests in the coming years.
As with Cancer, evidence is found on both sides. There are studies linking the consumption of milk and dairy products with Type 1 Diabetes (which in turn is highly influenced by genetic predisposition) and find that a consumption of low-fat dairy products is associated with a lower incidence of the disease (source) (source).
However, other studies suggest that CLA, actually present in milk fat as said before, would reduce the risk (source).
In the case of Type 2 Diabetes (acquired mainly due to bad habits) there is also an improving effect (source).
In those cases, where the evidence is inconclusive, it is likely that each person’s genetic background is determining the susceptibility. My suggestion is to eliminate the consumption of milk or, if you really like it, try with minimal amounts and see what effects may come.
Osteoporosis is basically a progressive weakening of the bones caused by many factors such as lack of physical activity and hormonal imbalances (that is why it is so common in postmenopausal women).
We can also find mixed evidence regarding milk consumption.
There are association studies that link intake with protection against fractures (source) (source) while others indicate the opposite and even associate it with a higher risk of suffering them (source) (source).
However, when we analyze randomized clinical trials (higher quality studies), it is concluded that the consumption of milk and dairy increases bone mineralization or, in the worst case, prevents its demineralization (source) (source) (source).
What we need to understand is that your body needs calcium to carry out multiple functions. If you do not provide the necessary through food, it will take the stored in the bones and that is what we want to prevent.
Apart from milk, there are other good sources of calcium such as fish (sardines, mackerel, salmon) or leafy vegetables, especially cruciferous which, from an evolutionary perspective, have way more common sense to ingest for an adult than milk (source) (source) (source).
Although milk does not integrate the elite group of what I call the 4 fundamentals and we can perfectly dispense its consumption, it has been unfairly blamed as a poison.
If you are part of the 30% of the population that is able to digest it without problems, you have good insulin sensitivity and there is no history of cancer in your family (especially Prostate Cancer), there shouldn’t be any problems in consuming 1-2 glasses a day. It will give you a good mix of various nutrients.
Ideally you want it to be full cream, pasteurized and from grass fed cows.
In the next posts we will talk about the other four alleged White Poisons.