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Does sugar destroy B vitamins?

Sugar’s effect on B vitamins is a common concern. Many people wonder if consuming sugar destroys B vitamins in the body or prevents their absorption. This article will examine the evidence behind this claim and provide a nuanced look at how sugar interacts with B vitamins.

What are B vitamins?

B vitamins are a group of 8 essential micronutrients:

  • B1 (thiamine)
  • B2 (riboflavin)
  • B3 (niacin)
  • B5 (pantothenic acid)
  • B6 (pyridoxine)
  • B7 (biotin)
  • B9 (folate/folic acid)
  • B12 (cobalamin)

These vitamins help convert food into energy and play key roles in cell metabolism and neural function. Unlike fat-soluble vitamins, they are water-soluble, meaning excess amounts are excreted in urine rather than stored long-term. As a result, B vitamins must be continually replenished through diet.

Deficiencies in B vitamins can cause symptoms like weakness, fatigue, confusion, mouth sores, poor growth, and anemia. Getting adequate B vitamins is essential for good health.

Do B vitamins get destroyed by sugar?

There is no evidence that consuming sugar chemically destroys B vitamins or renders them inactive. Both sugar and B vitamins remain biochemically stable when ingested together.

However, there are a few mechanisms by which sugar could potentially impact B vitamin levels indirectly:

1. Impaired absorption

Some studies suggest that high sugar intake may impair the absorption of certain B vitamins like thiamine, biotin and vitamin B12 in the gut. The mechanism is unclear but could be related to gut bacteria changes or interference with transporters that absorb B vitamins.

2. Increased excretion

Consuming large amounts of carbohydrates and sugar causes a rise in insulin levels. This triggers more thiamine to be excreted in urine. So a high-sugar diet can deplete thiamine over time.

3. Dilution of nutrient density

Foods high in added sugars like sweets, sodas and desserts are often nutritionally poor. Consuming excess sugar displaces more nutrient-dense foods in the diet, indirectly lowering B vitamin intake over time.

So in summary, while sugar does not directly destroy B vitamins, it could potentially contribute to marginal deficiencies by inhibiting absorption, increasing excretion and diluting the diet. However, this effect requires very high intakes of added sugar.

What is the daily requirement for B vitamins?

The Recommended Dietary Allowance (RDA) for each B vitamin is:

B Vitamin RDA for adults
B1 (thiamine) 1.2 mg
B2 (riboflavin) 1.3 mg
B3 (niacin) 16 mg
B5 (pantothenic acid) 5 mg
B6 (pyridoxine) 1.3 mg
Biotin 30 mcg
Folate 400 mcg
B12 2.4 mcg

These RDAs are set to meet the needs of over 97% of healthy individuals. Those with medical conditions like alcoholism, digestive disorders, diabetes or kidney disease may require higher intakes of certain B vitamins.

What foods provide B vitamins?

Many foods deliver B vitamins:

B1 (thiamine)

– Whole grains (especially enriched grains)
– Pork
– Legumes
– Nuts and seeds
– Seafood

B2 (riboflavin)

– Dairy products
– Eggs
– Meat (especially organ meats)
– Green vegetables
– Mushrooms

B3 (niacin)

– Meat and poultry
– Fish
– Whole grains
– Peanuts
– Potatoes

B5 (pantothenic acid)

– Meat
– Poultry
– Seafood
– Whole grains
– Broccoli
– Avocados

B6 (pyridoxine)

– Meat
– Poultry
– Fish
– Starchy vegetables
– Fruit (excluding citrus)


– Eggs
– Meat
– Seafood
– Nuts and seeds
– Sweet potatoes


– Legumes
– Dark leafy greens
– Asparagus
– Broccoli
– Citrus fruit
– Fortified grains


– Meat
– Fish
– Shellfish
– Eggs
– Fortified plant-based milk

As you can see, both animal and plant foods can be great sources of B vitamins. Variety is important.

Can you get too much of B vitamins?

Most B vitamins are considered very safe, even in high doses. However, extremely high intakes over a long period may be problematic for certain B vitamins:

– Vitamin B3: Doses over 3,000 mg per day have been linked to liver toxicity.

– Vitamin B6: Chronically high doses over 200 mg per day can cause nerve damage.

– Folic acid: Amounts over 1,000 mcg per day can mask B12 deficiency symptoms.

Unless taking high-dose supplements, toxicity is very rare. Absorption and excretion tend to limit the amounts of B vitamins obtained from food.

Do B vitamins get depleted by stress?

Physical and psychological stress does appear to increase the demand and quicken the breakdown of certain B vitamins like vitamin C, B5, B6 and B12.

Deficiencies may develop more quickly in those under chronic stress, making sufficient intake more important.

If B vitamin status is already marginal, stress can deplete stores. Supplementation may help replenish levels in some cases.

Do diabetics need more B vitamins?

Those with diabetes may be at higher risk of B vitamin deficiencies, especially B1, B6, B12 and biotin.

Reasons include:

– Altered digestion and absorption
– Kidney dysfunction increasing excretion
– Use of diabetes medications like metformin that deplete levels

Additionally, high blood glucose causes more vitamin C to be excreted through urine.

Checking vitamin B status in diabetics is advisable. A 25-50% increased intake of B vitamins through diet or supplementation may help meet needs.

Can B vitamins help with energy and metabolism?

Yes, B vitamins play crucial roles in energy production and metabolism:

– B1 helps the body extract energy from carbohydrates.

– B2 is important for using oxygen during energy metabolism.

– B3, B5, and B7 assist with conversion of nutrients to energy.

– B12 and folate help form DNA and red blood cells.

So getting sufficient B vitamins can promote normal energy levels, metabolic rate, and endurance during exercise. Deficiencies lead to fatigue.

However, mega-doses beyond the RDA have not been shown to further enhance energy or metabolism in those already getting adequate intake from their diet.

Do B vitamins interact with medications?

Yes, B vitamins can interact with certain medications. Examples include:

– Anticonvulsants: May increase need for B6, folate and B12.

– Birth control pills: Can deplete several B vitamins like B2, B6, folate and B12.

– Antibiotics: Some decrease biotin, B12 and folate absorption.

– Diabetes drugs: Metformin is known to deplete B12 and possibly thiamine.

– Acid blockers: May impair absorption of B12, requiring supplemented forms.

Those on medications should consult their doctor about potential interactions with B vitamins. You may need to supplement or eat more vitamin-rich foods.

Can you get B vitamins from a plant-based diet?

It’s possible to get adequate B vitamins on a vegetarian or vegan diet. Plant sources of B vitamins include:

– Folate: legumes, greens, citrus fruit, fortified grains

– B1: whole grains, nuts and seeds

– B2: mushrooms, almonds, wild rice

– B3: peanuts, mushrooms, potatoes

– B5: avocados, broccoli, whole grains

– B6: pistachios, potatoes, bananas

– Biotin: nuts, sweet potatoes, soybeans

However, B12 is only found naturally in animal foods. Vegans should take a B12 supplement or consume fortified foods. Nutritional yeast is a good option.

Those avoiding animal products should pay more attention to getting enough B vitamins, especially B12.


In summary, there is no strong evidence that sugar directly destroys or inactivates B vitamins. However, very high sugar intakes may potentially contribute to marginal deficiencies over time by interfering with absorption and increasing excretion.

Maintaining adequate B vitamin status is important for health, energy and metabolism. Both plant and animal foods can provide B vitamins in a balanced diet, though vegans may need supplementation for B12.

Those on medications, having digestive issues, or with diabetes may be more prone to B vitamin depletion and require testing and increased intake. Otherwise, for most people consuming a varied, whole food diet, B vitamin deficiencies are rare.