Why supplements are even more important in summer than in winter
Most people reach for supplements as soon as the days get shorter. It makes sense: less sun and more time indoors. But it’s also worth paying attention to your diet and supplements during the summer months. More sweating, more intense activity, disrupted eating habits due to vacations and longer days: these are all factors that increase your nutrient needs. In this article, you’ll learn which supplements are relevant for summer and why.
Why summer calls for extra attention
More sweating = greater mineral loss During intense exercise or in hot weather, you lose not only fluids through sweat, but also electrolytes and minerals such as magnesium, sodium and potassium. How much that is varies widely by person, effort and temperature. You get magnesium mainly from ordinary food (see below).
More UV exposure Although UVB radiation is necessary for vitamin D production, excessive UV exposure causes oxidative stress in the skin. Vitamin C contributes to the protection of cells from oxidative stress**.
Vacation disrupts your routine Irregular eating habits, different foods, alcohol, less sleep: on vacation, your routine goes out the window. That’s precisely when it’s useful to know which essential nutrients you may be lacking.
1. Magnesium: what you lose through sweat
Magnesium is a mineral you get mainly from food. Your gut, kidneys and bones together regulate how much magnesium your body absorbs, stores and excretes (de Baaij et al., 2015, Physiological Reviews).
There are approved EU health claims for magnesium, but we do not use them for our Magnesium complex. That is why we make no statements here about what magnesium does for you in summer. You can read more about forms, dosage and the upper limit in our article on magnesium supplements.
Recommended daily intake: 350 mg for men, 300 mg for women.
Food sources: whole grains, spinach, nuts, legumes and potatoes (Volpe, 2013).
Which form should you choose?
In a supplement, magnesium is always bound to another substance. Which form is absorbed best is less clear than is often claimed:
- Magnesium oxide: a lot of magnesium per gram, dissolves poorly in water.
- Magnesium citrate: dissolves well, commonly used in supplements.
- Magnesium malate: bound to malic acid.
- Magnesium bisglycinate: bound to the amino acid glycine.
In a study in magnesium-depleted rats, organic magnesium salts were absorbed slightly better than inorganic ones such as oxide and sulfate (Coudray et al., 2005, Magnesium Research). Whether that difference matters much in humans is not clear.
View GOYU Magnesium Complex on getgoyu.com
2. Vitamin C: more sun, more attention
Vitamin C is a well-known antioxidant. The following health claims for vitamin C have been approved, among others: Vitamin C contributes to the protection of cells from oxidative stress**. Vitamin C contributes to normal collagen formation for the normal function of the skin**.
Collagen is the structural protein of the skin. Exposure to UV radiation increases collagen breakdown and generates free radicals in the skin. For an overview of the role of vitamin C in the skin, see Pullar et al. (2017, Nutrients).
Recommended daily amount: 75 mg (minimum). Requirements may be higher with greater UV exposure or intense exercise.
Food sources: red bell pepper (190 mg/100g), kiwi, strawberries, broccoli, citrus fruits.
Note: vitamin C is sensitive to heat. Eating it raw or lightly steaming it preserves more of the vitamin than cooking it for a long time.
3. Vitamin D: the summer paradox
You might think you produce enough vitamin D in summer. The reality is more nuanced.
In the Netherlands, sunlight is strong enough to produce vitamin D only between 11:00 and 15:00 from April through September, and only if you are actually outdoors with your skin exposed to the sun. People who work in offices, use sunscreen (SPF 15 blocks ~93% of UVB), or have darker skin produce considerably less vitamin D than they think (Holick, 2007, New England Journal of Medicine).
We call this the summer paradox: feeling like you get enough sun, while your blood levels actually remain suboptimal.
Scientific research shows that a large proportion of the Dutch population also falls below the recommended blood level of 50 nmol/L during the summer months (Lips et al., 2010, European Journal of Nutrition).
The following health claims for vitamin D have been approved, among others: Vitamin D contributes to the normal function of the immune system**. Vitamin D contributes to the maintenance of normal bones**.
Recommended daily amount: 10 micrograms (400 IU) for adults; 20 micrograms (800 IU) for people over 70.
Food sources: oily fish (salmon, herring, mackerel), eggs, liver, fortified dairy products.
4. Omega-3: EPA and DHA
A less obvious supplement: omega-3 fatty acids (EPA and DHA). Research is underway on omega-3 in combination with sport and exercise, but there is no approved health claim for this.
For example, a study by Smith et al. (2011, American Journal of Clinical Nutrition) looked at omega-3 supplementation and muscle protein production in older adults. That’s interesting, but it’s no promise about your recovery.
This claim is approved: EPA and DHA contribute to the normal function of the heart**. The beneficial effect is obtained with a daily intake of 250 mg of EPA and DHA.
Recommended daily amount: 250-500 mg of EPA+DHA per day (EFSA reference value for the maintenance of normal heart function).
Food sources: oily fish (twice a week), walnuts, flaxseed (ALA only, which is converted to EPA/DHA less efficiently).
Summary: a roundup of summer supplementation
Supplement |
Why in summer |
Approved claim |
|---|---|---|
Magnesium |
Loss through sweat, more activity |
No claim: we do not use health claims for our Magnesium complex. |
Vitamin C |
More sun, more UV |
Vitamin C contributes to the protection of cells from oxidative stress**. Vitamin C contributes to normal collagen formation for the normal function of the skin**. |
Vitamin D |
The summer paradox: insufficient production |
Vitamin D contributes to the normal function of the immune system**. Vitamin D contributes to the maintenance of normal bones**. |
Omega-3 |
Little oily fish in your diet |
EPA and DHA contribute to the normal function of the heart** (at 250 mg of EPA and DHA per day). |
Disclaimer
The information in this article is intended for general guidance and does not replace medical advice. If you have concerns about deficiencies, always consult a doctor or dietitian. Supplements complement, but do not replace, a varied diet.
Frequently asked questions (FAQ)
Should I take all four supplements at the same time? No. Decide what’s relevant based on your lifestyle and diet. Office workers who spend little time outdoors would do well to keep taking vitamin D, even in summer.
Can I get too much vitamin D? Yes, at extremely high doses (above 4000 IU per day over a long period), vitamin D can be harmful. Stick to the recommended doses or have your blood levels tested.
Is it a problem if I forget to take my supplement for a week while on vacation? No. Most fat-soluble vitamins (D, A, E, K) are stored in body fat and do not need to be replenished daily. Vitamin C is water-soluble and is stored for a shorter time, but a week's break has no dramatic consequences.
When is the best time to take supplements? Magnesium: our directions say during or shortly after a meal. Vitamin D: with a meal (fat-soluble). Vitamin C: can be taken at any time.
Scientific sources
Volpe, S.L. (2013). Magnesium in disease prevention and overall health. Advances in Nutrition, 4(3), 378S-383S. PubMed
de Baaij, J.H.F., Hoenderop, J.G.J., & Bindels, R.J.M. (2015). Magnesium in man. Physiological Reviews, 95(1), 1-46. PubMed
Coudray, C., et al. (2005). Study of magnesium bioavailability from ten organic and inorganic Mg salts in Mg-depleted rats. Magnesium Research, 18(4), 215-223. PubMed
Pullar, J.M., Carr, A.C., & Vissers, M.C.M. (2017). The roles of vitamin C in skin health. Nutrients, 9(8), 866. PubMed
Holick, M.F. (2007). New England Journal of Medicine, 357(3), 266-281. PubMed
Lips, P., et al. (2010). Current vitamin D status in European and Middle East countries. European Journal of Nutrition, 49(3), 131-145. PubMed
Smith, G.I., et al. (2011). Dietary omega-3 fatty acid supplementation increases the rate of muscle protein synthesis in older adults. American Journal of Clinical Nutrition, 93(2), 402-412. PubMed
**Approved health claim (Regulation (EU) No. 432/2012)
