Weight loss Diets and Dietary Supplements: Your questions answered

One of you asked: Do I need to take a vitamin D supplement in winter?

Vitamin D is an important vitamin that we need to regulate the amount of calcium and phosphorous in our bodies. This in turn keeps our bones, immune systems, muscles and teeth healthy.

Where do we get vitamin D?

While we do get some vitamin D from our diet in foods such as eggs and oily fish, we tend to get the majority of our vitamin D from the sun. To make the most of that summer sun and to produce enough vitamin D to carry us through the winter, we recommend that our skin is exposed to sunlight for just a few minutes on most days of the summer. However, of course you should be careful not to get sunburnt, as this puts us at risk of skin cancer.

The sun is our biggest source of vitamin D

No matter how much skin you expose to the sun during winter, countries in the more norther latitudes simply do not get the right type of sunlight to produce vitamin D in our skin during the months of November to March. The sun is at too much of an angle to the northern countries during winter. Hence, the strength of the sun is reduced. And so during these months, you rely completely on the vitamin that you have stored from summer and on the vitamin D from your diet.

If you are not exposed to much sunlight over summer then your risk of vitamin D deficiency is much higher. We often see this in older adults who may be more homebound, or in people who cover up more of their skin when they leave the house. People with darker skin living in Northern latitudes are also more prone to vitamin D deficiency. This is becaue the pigmentation in their skin reduces the ability of the skin to produce vitamin D in response to the weaker sunlight at this latitude.

Who should take a vitamin D supplement?

As I mentioned in my previous post on diet supplements, there is just one sub group of our population that is formally recommended to take a vitamin D supplement. This policy recommends that all children under the age of 1 are to take 5ug of vitamin d a day. However, this policy is recently updated to include only babies who are breastfed or receive less than 300mls of infant formula (1).

However, the Food Safety Authority of Ireland produced dietary guidelines in 2011 (2) that suggest that a 5ug supplement of vitamin D may be useful for those over those between 5-50 years old. And a 10ug may be considered for everyone over the age of 50 years. While this is not a national policy, it does suggest that evidence is growing that perhaps standard vitamin D supplementation is beneficial for more than just young children.

Is there a risk of taking too much vitamin D?

There is emerging evidence that suggests that having vitamin d levels that are too high may have a negative effect on our health. And especially people who take a vitamin D supplement unnecessarily may be at risk of high vitamin D levels.

Should I get my vitamin D levels checked regularly?

It is definitely worth having your levels checked now and again, for example when you are getting a blood sample checked anyway for something else. Our blood vitamin D levels will give us a good idea whether a vitamin d supplement may be needed for you.

Be aware that your vitamin d levels will naturally be higher if they are checked in summer compared to winter. As a general rule, if your vitamin d levels are borderline low/normal in summer, you will likely be at risk of deficiency over the course of the winter.

To summarise my answer, while it may not be recommended for everyone to take a vitamin D supplement over the course of winter, it may be useful to have your vitamin d levels checked if you feel that you may be in an at risk group.

So another question I received was: Is intermittent fasting good for weight loss?

Intermittent fasting is definitely a type of dieting that seems to be growing in popularity. I actually reviewed some of the risks and benefits of this diet in my recent post on the most popular weight loss diets.

What is intermittent fasting?

Intermittent fasting diets can be generally divided into diets that require you to fast for one or more full days in a week, or diets where you fast between certain times of the day or night. While these diets may indeed lead to some weight loss, this is most likely because you are simply eating less calories (3).

Is intermittent fasting dangerous?

Intermittent fasting where you fast for one or more days a week is likely the more difficult and dangerous of the two forms of fasting, as it can leave people irritable and fatigued, and reduces productivity and your ability to exercise. Indeed calorie reduction will usually lead to weight loss, and many dietitians will strive for a calorie reduction when helping people to lose weight. However, a calorie reduction can be achieved in a much easier and safer way through healthy, balanced and far more sustainable diets.

What are the benefits of intermittent fasting?

One of the psychological elements of intermittent fasting that may help people to achieve calorie deficits is that by imposing a rule such as not eating for a day, or not eating after a certain time of the evening, they in some ways help to control their impulsivity to eat unhealthy foods. Rather than having to make small but constant little healthy choices throughout the day, a diet rule such as fasting for a day or a few hours takes away the decision making on healthy food choices during these times. However, ultimately you are not learning healthy behaviours. You are instead creating an eating pattern that very rarely matches your energy levels or that allows for schedule changes and social events.

Dietitian’s advice for starting an intermittent fasting diet

If you are eager to try intermittent fasting, I would recommend trying the overnight fast rather than a full day at a time. Imposing a small rule such ass not eating between 8pm and 7am may help you to manage evening snacking and help you to fall asleep with a more rested stomach. While healthy eating for weight loss does not usually require strict rules, and occasionally having a healthy late night snack will not completely “destroy” all your healthy eating efforts, trying to avoid late night snacking is definitely compat)ible with usual healthy eating practices!

One of you was wondering about the following question: Are there any foods I should eat to build up my immune system in winter?

What is our immune system?

Firstly, lets quickly look at what our immune system actually is, because this is a hugely complicated part of this question. Our immune system is the word we use to describe all our body’s systems that are in place to help us to fight off disease. It includes a whole range of organs, including our skin, our bone marrow, our spleen, our lymphatic system and more. It involves a whole host of cells including our many types of white blood cells and antibodies.

Are there any superfoods to help your immune system?

To answer your question bluntly, no there is not one or two super foods that will help us fuel our immune system over the Winter months. Our nutrition should come from as large a variety of foods as possible to make sure we get not just all the vitamins and minerals, but also the various antioxidants and phytonutrients that help us to stay well.

What can I do with my diet then to boost my immune system?

A diet that meets or preferably exceeds the recommended 5 a day of fruits and vegetables will help you to meet your requirements for many of the water-soluble vitamins and minerals that are linked to normal immune function.

There is also a small amount of research that suggests that a daily vitamin C supplement of over 200mg may reduce the severity and duration of the common cold (4). For those who are undergoing heavy and strenuous exercise, vitamin C supplements may also help to reduce your risk of getting a cold. And there is also some evidence that suggests that a zinc supplement taken during the cold and until the cold is gone may reduce the duration of a cold.

Also, if we are looking at our diet and our immune system as a whole, there is evidence to suggest that maintaining a healthy weight is key in keeping our immune system working normally. Being overweight or underweight may have a negative effect on how our immune system works.

And a question that a few of you asked was in: Do I need to avoid carbs to lose weight?

Carbs get a lot of bad rep!

To be honest, carbs get so much unnecessary bad rep! As I mentioned in my recent post on popular fad diets, there has been a version of a low carb weight loss diet doing the rounds for decades. Yet like with so many of the fad diets out there, weight loss is likely seen as a result of calorie restriction (by having to limit the amount of foods you can eat) rather than any effect from avoiding carbs. Research has shown that people on a low carb diet lose around the same amount of weight over the course of a year as people on a low fat diet which includes carbs.

How many Kcal are there in carbohydrates?

When you look at kcal per gram of a nutrient, carbs contain 4kcal/g and fats contain 9kcal/g. This means that fat is far more calorie dense than carbohydrates, and so a lower fat diet is still a very useful way to reduce your weight.

Does it matter what types of carbs I eat?

While healthy-eating guidelines do recommend that you avoid higher sugary indulgent foods when trying to lose weight, this is mostly because these types of food often provide us with excess calories without providing us with useful other nutrients such as fibre, vitamins and minerals.

It is important to consider carbs as more than just sugar. The term “carbs” also refers to starches and fibre. And diets especially high in fibre-rich foods such as wholegrains, pulses and vegetables are linked to healthier weights.

How big is a portion of carbohydrate foods?

While healthy eating does include regular consumption of high-fibre carb foods, be aware that recommended intakes of these foods are often much lower than what people usually eat. Our Irish food pyramid suggests that we eat 3-5 portions of carbohydrate foods, with one portion being:

2 slices of bread, 2 medium potatoes, or 1/3 cup of uncooked porridge.

Many of us would easily exceed our recommended portions of carbs, so consider looking over your own diet to see if a reduction in carbohydrate foods may be recommended for you.

I wrote a full post on the science behind what a carbohydrate is, which you can find here!

And then another great question: Are there any benefits in taking fish oil supplements?

There is a growing mistrust that our diet could simply not provide us with all that our body needs, but guys, this is not true! A healthy and well-balanced diet really can meet all the recommended daily allowances for our nutrients.

Are fish oils a fad?

Fish oils have been taken as a supplement for decades, originally in the form of a nasty spoonful of cod liver oil, and more recently in neatly packaged fish oil capsules. Fish oils are rich in an essential fatty acid group called Omega 3 fatty acids. These are essential for our brain, heart and joint health, to name but a few.

How much oily fish should I eat?

A mere two portions of oily fish a week will help you to meet your daily recommended amounts of omega 3 fatty acids. Oily fish include salmon, trout, herring, mackerel and sardines. And a portion is around 75g, or 2.5 ounces of these fish.

If you do not eat oily fish, you can still get some of your omega 3 fatty acids from a variety of plant foods such as rapeseed oil, walnuts, flaxseeds and soy products. Our body can then produce some of the fish-specific omega 3 fats from these plant sources.

Should I take a fish oil supplement?

At this time, there is no strong evidence available to suggest that taking an omega 3 supplement is better for our health than consuming our omega 3 fats from our diet. And so I would say, enjoy your oily fish and your plant-based sources of omega 3 fats. These not only help you to meet your daily omega 3 requirements, but will also provide you with a whole host of other nutrients, and some enjoyment!

I hope I have been able to answer your key questions in enough detail today. Of course feel free to continue asking questions, or get in touch to clarify any specific points! I will try to respond either via a personal message, or may cover your question (anonymously of course) in an Instagram story!

There is so much nutrition info out there online and on social media. And unfortunately a lot of the info available is biased, incorrect or occasionally even dangerous. So I really appreciate you guys seeking out dietitians and qualified healthcare professionals for your nutrition information.

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