COLUMN: Know your vitamins - here's all you need to know about Vitamin D

There are many nutrients, vitamins and minerals required for maintaining our health but Vitamin D really is an allrounder as it’s required for many body processes and has huge benefits in both the prevention and treatment of illness.

Here, nutritionist Laurann O’Reilly and owner of Nutrition by Laurann, explains everything you need to know about Vitamin D.

What is Vitamin D?

Vitamin D is an essential nutrient and critical for the development and normal functioning of many organs in the body and for maintaining optimal health throughout our whole lives.

Where Can We Get It?

We make Vitamin D by sun exposure via our skin, specifically ultraviolet B (UVB) rays, which is why it’s also known as “the sunshine vitamin”.

The World Health Organisation advice is to get 5 to 15 minutes of casual sun exposure to hands, face and arms two to three times a week during the summer months.

However, during the autumn and winter months the sun isn’t strong enough for us to make Vitamin D. We need to get our Vitamin D from our diet (HSE).

It can be found in small amounts of food products with Vitamin D2 (ergocalciferol) found in some plant-based products and Vitamin D3 (cholecalciferol) found in some animal-based products.

However, the richest dietary sources are found in fortified foods.

As it’s often difficult for people to get enough Vitamin D from food alone, The HSE recommends taking a daily supplement of Vitamin D during autumn and winter.

What Are The Benefits?

Whilst Vitamin D has numerous benefits here are some of the few

- Healthy Bones & Teeth- Vitamin D is essential for strong bones as it is required for the absorption calcium and phosphorus from food. These are both essential minerals for maintaining healthy teeth and bones whilst also helping to prevent osteoporosis.

- Supporting The Immune System - Evidence suggests that Vitamin D may have an important and supportive role for the immune system, particularly in regulating immune response and reduction of proteins known to trigger inflammation.

- Improving Gut Health - A study carried out last year found that Vitamin D supplementation can significantly increase the variety of our gut bacteria, which play an important role in digestion, immunity and hormone balance.

- Mood - As our bodies produce Vitamin D from sunlight, our levels of this vitamin can seriously decrease during the dark winter months. It has also been suggested that this drop in Vitamin D may be linked to ‘Seasonal Affective Disorder’ or SAD, a mood disorder which is also common in individuals during this time. This is because Vitamin D is involved in regulating the production of serotonin.

The Irish TILDA study also found that individuals over the age of 50 years are 75% more likely to experience depression if their Vitamin D levels are low.

- Respiratory Health - Vitamin D is known to assist in fighting bacteria and viruses and reduce acute respiratory infections.
An international study (the Jolliffe papers) showed “a 25% reduction of the risk of respiratory infections in those taking a daily vitamin D supplement”.

- Potential Use with Covid-19 - Most of us have now heard of the Oireachtas report published last year which discusses the potential role of Vitamin D in “preventing ill health and respiratory illness” and how “Vitamin D is known to assist the immune system in fighting harmful bacteria and viruses” along with “reducing the risk of acute respiratory (lung) infection”. Based on this report, they have recommended that the entire Irish population takes a Vitamin D supplement.

What Affects Our Vitamin D Levels?

Skin Pigmentation - People with darker skin are at higher risk of low Vitamin D due to a higher level melanin in their skin. Unfortunately, melanin reduces the ability of UVB rays to pass through the skin, lowering the body’s ability to make Vitamin D.

Age - As we age, our body’s ability to produce Vitamin D from the sun becomes less efficient due to the effect that the ageing process has on the skin.

A study comparing the amount of Vitamin D3 produced in the skin from the 8 and 18 year old subjects with the amount produced in the skin from the 77 and 82-year-old subjects revealed that the younger group had greater than twice the capacity to produce Vitamin D.

The Season - In Ireland we have reduced daylight hours from autumn to mid spring which limits our opportunity for creating Vitamin D.

Other factors which can limit our exposure to the sun are long hours working or studying indoors as well as a lack of opportunity to access the outdoors such as residents of nursing homes and as well as those who don’t have a safe outdoor recreation area.

Clothing - As we require our skin to be exposed to the sun in order to create Vitamin D and in Ireland it’s rarely warm enough to go without a jumper, jacket or scarf, this again impairs the chance for creating the vitamin.

Sun protection - It’s highly important to take care when exposing the skin to the sun to prevent skin cancer.

It has been shown that correct application of a product containing an SPF of 15 almost completely prevents skin production of

Vitamin D which is why adequate food sources and supplementation is important.

Deficiency

In addition to not getting enough sunshine in Ireland, the quality of sun generally doesn’t provide enough in UVB to generate adequate Vitamin D, particularly during the winter months to support our immune system.

The recent Oireachtas report discussed how deficiency is can be found across all age groups, with deficiency found in almost half of 18-39 year olds, over a third of 50-59 year olds, 64% of the over 80s, 67% of nursing home residents and 93% of BAME communities (black, Asian and minority ethnic).

Recommendation: The Oireachtas report released last year recommends that the entire Irish Adult population should take a supplement of 20-25 μg/day or 800-1000 IU/day, whilst children should take 10μg or 400IU/day as a public health measure as an aim to reduce the risk of respiratory conditions and other illnesses such as osteoporosis.

Note: If you have any pre-existing medical conditions, are taking medications, infants and young children please consult with your GP or pharmacist first.

Food Sources: Vitamin D can be found in oily fish such as mackerel, sardines, tinned salmon, herring and kippers and a small amount in sources such as red meat, liver and eggs.

Fortified milk such as super milk and cereals are also great sources.

The Oireachtas report suggests that the above supplement recommendation is taken alongside dietary sources in order to adequately meet requirements.

Supplements: The report also discusses the importance of Vitamin D supplementation not only for the Irish adult population but also for vulnerable groups such as those in nursing homes and health care workers.

Vitamin D supplements commonly come in the form of a spray or a capsule, when choosing a Vitamin D supplement, it’s best to choose Vitamin D3, which is the most efficient form of the vitamin and is also the most effective at improving the blood’s Vitamin D levels.

Supplement Recommendations: My preferred Vitamin D supplements are the PharmaNord BioActive Vitamin D pearls (available in a 38μg/1520 and a stronger 75μg/3000 IU), PharmaNord BioActive Vitamin D Pearls Junior 5 µg/200 IU (suitable for children over the age of 2) and Shield Health BabyVitD3 5 µg/200 IU Drops (suitable from birth).

Note: For Infants or young children please consult with your pharmacist or GP first.

Vitamin D Boosting Recipe
Baked Teriyaki Salmon With Wholegrain Rice
(Serves 4)
1 Salmon Darne = 292 IU Vitamin D

Ingredients
4 Darnes of salmon
1 Onion sliced
1 Tablespoon Sesame Seeds
Wholegrain Boil In The Bag Rice
Teriyaki Sauce:
⅓ Cup Low-sodium soy sauce
¼ Cup Fresh orange juice
2-3 Tablespoons Water
2 Tablespoons Honey
2 Garlic Cloves minced
1 Tablespoon Minced fresh ginger
1 Teaspoon Chili Flakes or to taste (option if you like a spicy kick)
½ Lemon juiced
½ Tablespoon plain flour

Directions
Preheat the oven to 200°Celcius
In a small bowl whisk together all teriyaki sauce ingredients
Spray a baking dish with non-stick cooking spray and place the salmon and onions in the dish.
Pour the sauce over then bake in the preheated oven for 12-15 minutes until cooked through and flaky
Whilst the salmon is cooking, boil the rice, following the cooking instructions on the box (this should take approximately 10 minutes)
Once the salmon is cooked, remove from the oven and pour over any remaining sauce from the baking dish
Serve on a bed of your prepared wholegrain rice
Sprinkle with sesame seeds and Enjoy!