As a dermatologist, I am often asked if there is a connection between nutritrion and a skin condition. We know the relationship between vitamin C deficiency and scurvy, too little iron can cause anemia, nail abnormalities or itching and zinc deficiency can lead to delayed wound healing. In recent years, more studies have been done on skin diseases such as acne, skin cancer, psoriasis, eczema, rosacea and the influence of diet.
Dermatologists have long denied the relationship between “bad” diet and acne on the basis of previous studies. But the most recent studies show that there is strong evidence that milk, unbalanced fatty acids and carbohydrate-rich foods can exacerbate acne.
Growth hormone in milk that stimulates the sebaceous gland
The hormones of cows in milk may have a comedogenic (sebaceous gland-clogging substance) effect. It is believed that milk contains a substance that stimulates the sebaceous gland. This is the insulin-like growth factor 1 (IGF-1). The level of this substance in the human body rises anyway during puberty, under the influence of growth hormone, and this coincides with the appearance of acne.
Too much omega-6 fatty acid stimulates inflammation
Western diets are often deficient in omega-3 and its precursor, αLA. In a typical Western diet, the ratio of omega-6 to omega-3 fatty acids can be as high as 10:1 to 20:1, compared to a ratio of 3:1 to 2:1 in non-Western diets or non-industrialized peoples . Omega-6 fatty acids are thought to have higher pro-inflammatory effects. They are therefore associated with the development of acne. On the other hand, the intake of high amounts of omega-3 fatty acids is associated with the reduction of inflammatory factors.
Be careful with quickly digestible carbohydrates
Then there is the glycaemia: the amount of fast-digesting carbohydrates in food that raises the blood sugar level can influence the triggering of acne vulgaris. A diet based on products with a high glycemic index (white bread, white rice, plain pasta, biscuits and sweets, etc.) leads to increased insulin production (hyperinsulinaemia). An elevated insulin level stimulates the secretion of androgens (male hormones) and causes increased sebum production, which plays a fundamental role in causing acne vulgaris.
The influence of chocolate has not been proven
So far chocolate is not on the acne stimulating food list.
Skin cancer (non melanoma skin cancer BCC and SCC)
Non-melanoma skin cancers such as basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) are the most common cancersr.
Lycopene, abundant in tomato paste
It has been shown that a diet rich in fruits and vegetables can provide overall protection against these skin cancers. Some studies showed that certain nutrients reduced some of the effects of photocarcinogenesis (transformation of normal cells into cancer cells by UV radiation). In a randomized study, the intake of tomato paste, which is rich in lycopene, was shown to protect the skin against the effects of UV radiation such as redness and DNA damage.
The orange dye from carrots
Other studies have shown that intake of beta-carotene and lycopene, found in carrots and tomatoes, can protect against UV-mediated damage.
Studies in humans have produced conflicting results when studied specifically for skin cancer. For example, studies on the use of antioxidant supplements generally do not support the prevention of skin cancer.
Little scientific evidence for protection of antioxidant supplements against skin cancer
A randomized study found that the use of an antioxidant supplement consisting of vitamin C, vitamin E, beta-carotene, selenium and zinc did not affect the incidence of basal cell and squamous cell carcinoma (BCC and SCC).
In a 12-year study of more than 22,000 male physicians, 50 mg beta-carotene supplement did not affect the development of first basal cell and squamous cell carcinoma.
A study showed an increased risk of squamous cell carcinoma by swallowing selenium
Another randomized trial showed that selenium supplementation is ineffective in preventing basal cell carcinoma, but increases the risk of squamous cell carcinoma.
It has been shown that patients with psoriasis often also suffer from other conditions such as obesity, diabetes, hypertension (increased blood pressure) and dyslipidaemia (increased values of total cholesterol, LDL cholesterol, triglycerides and decreased HDL cholesterol) and that they also have a higher risk of developing cardiovascular disease.
More likely to develop diabetes
An analysis of 27 different observational studies found that psoriasis is associated with both an increased risk of developing diabetes.
More likely to have elevated cholesterol
An overview of 25 observational studies, with more than 265,000 psoriasis patients, shows that psoriasis increases the risk of dyslipidemia (elevated cholesterol). The presence of psoriasis alone is an independent risk factor for myocardial infarction.
Diet to reduce cardiovascular disease risk in psoriasis patients
It is very useful to give dietary advice to patients with psoriasis to reduce the risks of cardiovascular disease. It has been shown that certain nutrients such as fruits and vegetables, unprocessed grains and omega-3 fatty acids (in oily fish, linseed oil, walnut and soybean oil) and fewer omega-6 fatty acids actually improve vascular inflammation, a risk factor for psoriasis patients.
Many psoriasis patients show an increased sensitivity to gluten and their symptoms improve on a gluten-free diet.
Atopic eczema and food allergies are highly correlated and sometimes also the cause of eczema. The most common nutrient triggers are milk, eggs, wheat, soy, nuts and seafood. These substances can cause an acute type 1IgE-related reaction after ingestion. An eczema flare can occur within minutes to hours.
Itching and hives
In 40-60% of cases, an IgE related food allergy. This is accompanied by itching and hives, without eczema. In addition to skin, throat, gastrointestinal and heart complaints can also arise. More on puritus
In case of complaints after 48 hours, food intolerance is often not clear
Complaints can also arise after 48 hours. Think of redness, scaling and itching. These are usually not related to IgE, the relationship with nutrition is therefore unclear.
Hypersensitivity to several nutrients at the same time is more common
In a food intolerance study to cow’s milk, chicken egg, wheat and soy in 106 children with atopic eczema, an eczematous reaction to 1 nutrient was observed in 6% of the children. In 21% of the children, an eczema reaction developed as a result of a combined food intolerance.
One substance can provoke a hypersensitivity to another substance
It can be even more complicated. Because a hypersensitivity to a perfume substance such as Balsam of Peru can cause your eczema to flare up after eating tomatoes, berries, cherries, or canal. Cross-reactions with other substances are also possible. As in the case of Peru balsam with benzoic acid, eugenol, cinnamic acid, benzoin, tolu balsam, wood tar, turpentine, propolis and storax (resin).
The usefulness of pre- and probiotics
Prebiotics (a collective name for indigestible carbohydrates and dietary fibres) provide relief from atopic eczema. Prebiotics are found in bread, fruit, vegetables, grain products and legumes. Probiotics are also regarded as positive (good intestinal bacteria) in a Cochrane review in 2013. Four studies with 1428 children showed reduced atopic dermatitis after taking prebiotic supplements.
In a meta-analysis of 16 studies, it was shown how beneficial probiotics were for people with normal eczema complaints as for people with a very high risk of eczema complaints. Specifically, a subgroup analysis showed that Lactobacillus and Lactobacillus with Bifidobacterium may also be protective against atopic dermatitis. However, the optimal dose, type of bacteria and duration of treatment with probiotics is still unclear.
Rosacea is a chronic skin condition in which facial redness usually does not go away on its own. Also, the nose is often red, swollen and full of pimples, the so-called “wine nose”. It is therefore a cosmetically disturbing skin disease.
Be careful with liqueur and white wine
However, a recent study of 82,737 American women found that alcohol increases the risk of rosacea. The researchers investigated whether it made a difference what the women drank. The biggest culprits appeared to be white wine and liquor.
More than 5 glasses per week gives an increased risk of 49% in women!
Researchers have found that one to three drinks per month increases the risk of developing rosacea by 14 percent. Drinking five or more glasses of white wine a week increases the risk by 49 percent. Red wine and beer seem to be a safe alternative. In men, it has not been studied.
Increasing attention to the gut-skin connection
The influence of nutrition is an underexposed item in the treatment of certain skin conditions. Fortunately, there are more studies focussing on this subject. A new way of looking is the skin-gut axis. The influence of intestinal bacteria and the skin is receiving increasing attention. Intestinal bacteria react to your diet and an imbalance of good bacteria due to bad eating habits affects the immune system. This has consequences for your skin and intestines.