V is for Vitamins Part 1 Fat soluble vitamins A,D, E and K
Updated: Nov 25, 2022
“Affirmations are our mental vitamins, providing the supplementary positive thoughts we need to balance the barrage of negative events and thoughts we experience daily” (Tia Walker) but our bodies need vitamins from the food we eat to function and maintain optimal health.
There are 13 essential vitamins required for the body to function divided into two types of vitamins fat-soluble (which are stored in fatty tissue and need to be consumed with fat for optimal absorption – Vitamins A, D, E and K) and water-soluble vitamins (which are used immediately and any excess are excreted in your urine – Vitamins C, B1, B2, B3, B5, B6, B9, B12* and Vit B7 (sometimes called Vit H) (* NB Vitamin B12 is water-soluble but can be stored in the liver for years)
All vitamins were identified between 1913 and 1948. The term ‘ vitamin’ derives from the word vitamine, coined in 1912 by Polish biochemist Casimir Funk, who isolated a complex of micronutrients essential to life, all of which he presumed to be amines. When this presumption was later found not to be true, the ‘e was dropped from the word.
So what is the function of each vitamin and how can we include it in our diet ? This first post is going to look at the fat-soluble vitamins
Vit A (Retinol)
Vitamin A is found naturally in many foods but is also added to some foods, such as milk and cereal. Vitamin A is important for normal vision, the immune system and reproduction. It also helps the heart, lungs, kidneys and other organs work properly.
There are two different types of vitamin A :
Pre-formed vitamin A is found in meat (eg liver, poultry), fish (eg fish liver oil, tuna (bluefin), mackerel and oysters) and dairy products (eg egg yolks).
Provitamin A is found in fruits (e.g.dried apricots, cantaloupe, tropical fruit especially mango and papaya), vegetables (eg sweet potatoes, carrots, dark leafy greens (kale), winter squash (butternut squash), lettuce (Cos or Romaine) red bell peppers) and other plant-based products. The most common type of provitamin A in foods and dietary supplments is beta-carotene.
Vit D (D2 Ergocalciferol/D3 Cholecalciferol)
Vitamin D helps your body absorb calcium, thereby helping to protect you from developing osteoporosis. It is also required for our immune system to fight off bacteria and viruses, to enable your muscles to move, and your nerves to carry messages between your brain and your body. There have been various studies linking low vitamin D levels with increased risk of Alzheimer’s, dementia and cognitive decline (see below)
Your body makes some vitamin D when your bare skin is exposed to the sun, but clouds, pollution, old age, and having dark-coloured skin reduces the amount of vitamin D your skin makes. Because ultraviolet radiation from sunshine can cause skin cancer we often use sun tan lotions to protect our skin and limit how much time we spend in the sun which obviously has a knock-on effect on our absorption levels (NB your skin does not make vitamin D from sunlight through a window).
There are two different types of vitamin D
Vitamin D2 mainly comes from plant sources and fortified foods ; as very few foods naturally contain vitamin D fortified foods or supplements provide most of the vitamin D in our diets and since vitamin D2 is cheaper to produce, it's the most common form in fortified foods.
Vitamin D3 is only found in animal-sourced foods Both forms of vitamin D in supplements increase vitamin D in our blood, but D3 might raise it higher and for longer than D2.
Foods rich in vitamin D include : fortified cereals/juices/milk, cod liver oil, oily fish (eg trout, smoked salmon, sword fish, canned trout, salmon, mackerel and tuna(, butter, extra lean ham, tofu, caviar, soy yoghurt, almond milk plus traces are found in cheese (esp ricotta), egg yolks, portabella mushrooms
NB bananas are a great source of magnesium, which plays an important role in activating vitamin D in the body once it enters the blood stream. Other magnesium-rich food are spinach, almond, peanuts, pumpkin seeds and cashew.
Vit E (Tocopherols/Tocotrienols)
Vitamin E acts as an antioxidant, helping to protect cells from the damage caused by free radicals which are compounds formed when our bodies convert the food we eat into energy. We are also exposed to free radicals in the environment from cigarette smoke, air pollution, and ultraviolet light from the sun.
The body also needs vitamin E to boost its immune system so that it can fight off bad bacteria and viruses. It helps to widen blood vessels and keep blood from clotting within them. Cells also use vitamin E to interact with each other and to carry out many important functions.
There are two different types of vitamin E
Tocopherols whose molecular structure have a longer tail (phytyl) exist in four forms designated as α, β, δ and γ. Due to their strong antioxidant properties, tocopherols have been suggested to reduce the risk of cancer. (Cancer prevention studies with tocopherols have mostly utilized α-tocopherol )
Tocotrienols whose molecular structure have a shorter, more flexible tail (farnesyl). This small difference in molecular structure allows tocotrienols to cover a larger surface area of the cell membrane more quickly, hence making them more effective as antioxidants. Research suggests that tocotrienols have an overall positive effect on human health, being potent antioxidants, carrying anticancer properties reducing risk of cardiovascular disease and lowering cholesterol levels. Tocotrienols may also help slow the build up of plaque in the arteries and decrease cholesterol levels.
Vitamin E is found naturally in oils (eg olive oils, wheat germ, sunflower, grapeseed, hazelnut oil and safflower oils ) soybean oil, tofu and nuts (e.g. almonds, pinenuts, peanuts, hazelnuts, brazil nuts) seeds (e.g. roasted sunflower seeds) shellfish (eg shrimp, crayfish, oyster) fish (rainbow trout, swordfish, Atlantic salmon) meat (eg goose meat) avocados and smaller amounts can be found in other vegetables ( e.g. cooked spinach, red peppers and broccoli) fruit (eg mango, kiwi) and squashes/pumpkins eg butternut squash. It is also added to some fortified foods eg . breakfast cereals, fruit juices, margarines and spreads,
Vit K (Phylloquinone K1/Menaquinone K2)
Vitamin K is a nutrient that is important for blood clotting and healthy bones.
There are two different types of vitamin K
Vitamin K1 also called phylloquinone travels straight to the liver and supports healthy blood clotting. It is mostly found in plant foods like leafy green vegetables (e.g. spinach, kale, broccoli, and lettuce) vegetable oils and some fruits (e.g. blueberries and figs)and makes up about 75–90% of all vitamin K consumed by humans
Vitamin K2 is found in fermented foods and animal products, and is also produced by gut bacteria. Vitamin K2 goes directly to the blood vessel walls, bones and tissues but bypasses the liver.
It has two sub categories:
MK4 which is a short-chain form of Vit K2 and is found in meat (lamb, duck, beef liver, dark turkey meat, chicken liver, full fat grass fed, hormone/antibiotic free cows), butter, egg yolks, cheese (eg Gouda and brie) and other animal based foods.
MK7 is a longer-chain form of Vitamin K2 – natural bacteria found in fermented foods. It has the advantage that is stays in the body longer so you only need to take it once a day
Vitamin K2 works in synergy with other nutrients or co-factors eg calcium, magnesium and Vitamins D & A. Vitamin K2 escorts calcium to the areas of the body where it needs it the most eg it takes calcium to the bones and teeth and away from the arteries and soft tissue
Vitamins (and minerals) are required to strengthen bones, heal wounds and boost our immune system. They also convert food into energy, and repair cellular damage. Although experts agree that the best way to get the nutrients we need is through food, by eating a balanced diet — one containing plenty of fruits, vegetables, and whole grains (barley, oats, quinoa, brown rice*) that collectively meet the body's needs, there are some scenarios where additional vitamin tablets maybe required particularly during the Winter months in the northern hemisphere when there are less hours of sunlight, pregnancy etc
Most foods provide multiple sources of vitamins. Here is a summary of those foods mentioned containing high levels of Vitamins A, D, E and K. Those with stars are considered nutrient-dense foods (Foods that have a lot of nutrients relative to the number of calories).
Summary of foods mentioned:
Fortified cereals/juices/milk/margarine and spreads
liver, chicken*, extra lean ham, goose meat, lamb*, duck, beef liver, dark turkey meat*, chicken liver, venison*, full fat grass fed, hormone/antibiotic free cows*
tuna* (bluefin), mackerel, rainbow trout, swordfish, Atlantic salmon*, smoked salmon, caviar, shellfish (eg shrimp*, crayfish, oyster)
Egg yolks, butter, ricotta cheese, Gouda, Brie,other cheeses, low-fat yoghurt*, eggs*
dried apricots, cantaloupe, tropical fruit especially mango, kiwi and papaya*, blueberries, figs
avocados*, sweet potatoes, carrots, dark leafy greens -kale*, cooked spinach*, mustard greens*, chard*, broccoli, lettuce (esp Cos or Romaine) brussel sprouts*, ; lettuce red bell peppers*, portabella , crimini and shiitake mushrooms*, soy, tofu fruit and squashes/pumpkins eg butternut squash.
Fish liver oil, olive oils, wheat germ, sunflower, grapeseed, hazelnut oil, safflower oils and soybean oil
almond milk, almonds*, pinenuts, peanuts*, hazelnuts, brazil nuts
roasted sunflower seeds* sesame*
If you want to reflect more on this subject, here are some links to get you started:
Low Vitamin D and Its Association with Cognitive Impairment and Dementia (2020)
Vitamin D deficiency as a risk factor for dementia and Alzheimer’s disease: an updated meta-analysis (2019 study)
Vitamin D and Dementia (2014)