Bioavailability of Vitamin C – from sea buckthorn and other sources

Vitamin C is one of the key vitamins your body needs to function properly. Even people with little prior knowledge of vitamins and dietary supplements often wonder how they can consume more vitamin C. Since the human body cannot produce vitamin C itself, we need to obtain it from our diet – sea buckthorn is an excellent source, as its vitamin C content is up to 10 times higher than that of citrus fruits.

But what is the best way to consume natural vitamin C supplements? This is where the term bioavailability comes into play. However, questions about which foods contain particularly high levels of vitamin C and how synthetic and natural vitamin C differ should not be overlooked either.

What does bioavailability mean?

If a substance is bioavailable, this means that it can be absorbed by the body, for example from food or dietary supplements. The more natural these nutrients are, the more readily they can be absorbed and metabolized. Compared with natural nutrients, synthetically produced ones have the disadvantage that they may not be absorbed in full and may therefore be excreted unused. As a result, the desired effect does not occur.

At first glance, the logical approach when taking vitamin C would therefore be simply to consume more of it so that the body absorbs a higher amount in any case. However, one thing must be taken into account: The more vitamin C you consume per serving, the less of it the body absorbs into the cells. This is described using the so-called absorption rate as a percentage:

Single dose (oral)	Absorption rate in %
100–200 mg	90–100
1000 mg	60–75
3000 mg	40
12000 mg	16

Studies by Levine et al. show that maintaining the body’s 3000 mg vitamin C reserves requires a daily oral intake of 200 mg. Immune cells such as monocytes and lymphocytes are already saturated with a daily intake of 100 mg of vitamin C. Complete plasma saturation is achieved with an intake of 1000 mg of vitamin C per day, although it is more sensible to take five individual doses of 200 mg rather than 1000 mg all at once.

What does the body need vitamin C for?

The body relies on an adequate intake of bioavailable vitamin C because vitamin C is needed for a wide range of processes, including:

• contributes to the normal function of the immune system
• protects against oxidative stress, so-called free radicals
• reduces tiredness and fatigue – partly by promoting iron absorption
• stimulates the liver’s enzyme system – improves detoxification
• cofactor in the formation of collagen – strengthens connective tissue and ensures elasticity in the skin, joints and muscles
• necessary for the formation of neurotransmitters responsible for transmitting nerve impulses
• promotes the production of thyroid hormones
• regulates histamine levels (histamine is released in increased amounts during allergic reactions)

Vitamin C content of different foods

Food	Vitamin C in mg/100 g
Camu-camu berry Acerola Rose hip Sea buckthorn Kiwi Lemon Orange Banana Bell pepper Broccoli Red cabbage Tomato Beef liver Milk	2000 1700 1250 800 80 53 50 12 138 115 50 38 33 1

Sea buckthorn is an excellent source of vitamin C, although the vitamin C content of sea buckthorn depends on its origin. Berries from coastal regions or Asia contain 200 to 400 mg of vitamin C per 100 g of fruit, while in the Alpine region the figure is around 1500 mg per 100 g.

The content of bioavailable vitamin C also remains constant during storage in sea buckthorn, which is partly due to the low pH value of sea buckthorn of 2.5. Since vitamin C is sensitive to heat, gentle processing is crucial to preserving the vitamin C, which is why our Fresh Elixir is produced using the cold-stirring process.

What is the difference between natural and synthetic vitamin C?

What is generally referred to as vitamin C is, from a chemical perspective, L-ascorbic acid as well as chemical derivatives that can be converted into vitamin C in the body (e.g. dehydroascorbic acid). From a chemical perspective, natural vitamin C preparations and synthetically produced vitamin C, i.e. vitamin C produced in a laboratory, are identical.

Caution is advised when it comes to the terms used for vitamin C preparations: “pure” vitamin C means that it is synthetically produced and does not come from natural sources; “buffered” vitamin C means that, to improve tolerability, it is bound to a basic mineral during production. Synthetically produced vitamin C is also sold under the designation liposomal vitamin C, meaning that the vitamin C is enclosed by fat droplets (liposomes) to improve absorption in the body.

What matters, however, is how much vitamin C the body can absorb from which sources. In this respect, vitamin C from natural sources such as sea buckthorn offers the advantage that the body also absorbs additional macro- and micronutrients.